Citation Nr: 1620792 Decision Date: 05/23/16 Archive Date: 06/02/16 DOCKET NO. 11-26 597A ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in Winston-Salem, North Carolina THE ISSUES 1. Entitlement to service connection for glucose-6-phosphate dehydrogenase (G6PD) deficiency, for substitution and accrued benefits purposes. 2. Entitlement to a total disability rating based on individual unemployability (TDIU), for substitution and accrued benefits purposes. REPRESENTATION Appellant represented by: The American Legion ATTORNEY FOR THE BOARD B. Muetzel, Associate Counsel INTRODUCTION The Veteran had active service from June 1976 to June 1979. He died in September 2009; the Appellant is his surviving spouse. This matter comes before the Board of Veterans' Appeals (BVA or Board) from a January 2010 rating decision of the Department of Veterans Affairs (VA) Regional Office (RO) in Philadelphia, Pennsylvania. A Notice of Disagreement (NOD) was received in October 2010, a Statement of the Case (SOC) was issued in August 2011, and a substantive appeal was received in September 2011 through the Veterans On Line Applications (VONAPP) system. Additionally, a VA Form 9 was received in October 2011. Jurisdiction over the matter is retained by the RO in Winston-Salem, North Carolina. The appellant indicated on her September 2011 VA Form 9 that she wished to testify at a Board video conference hearing. She also requested a local hearing before a Decision Review Officer in August 2011. However, the appellant later withdrew these hearing requests. See November 2011 statement (I am not requesting a BVA hearing via teleconference) and August 2013 report of general information ("widow DID NOT want a hearing and would like [the] DRO to make the decision"), 38 C.F.R. § 20.704 (2015). In September 2014, April 2015, and July 2015 the Board remanded these claims for additional development. For claimants who died on or after October 10, 2008, (as is the case here), the Veterans' Benefits Improvement Act of 2008, Pub. L. No. 110-389, § 212, 122 Stat. 4145, 4151 (2008) created a new 38 U.S.C. § 5121A, which permits an eligible person to file a request to be substituted as the Appellant for purposes of processing the claim to completion. In this case, the record reflects that in November 2014, the RO determined the Appellant was the surviving spouse of the Veteran, and that she was a proper person to be substituted as claimant in the Veteran's claims for VA benefits, which were pending at the time of his death. See November 2014 letter. However, the RO has adjudicated the claims solely for accrued benefits purposes pursuant to 38 U.S.C.A. § 5121. There is an important distinction between the law governing a claim for accrued benefits upon the death of a beneficiary and claims regarding substitutions of claimants in the case of death of a claimant. 38 U.S.C.A. §§ 5121, 5121A (West 2014). When adjudicating the accrued benefits claims, only the evidence record at the time of death may be considered as the basis for a determination on the merits of the claim. When a properly qualified substitute claimant continues the pending claim in the footsteps of the Veteran after death, additional development of the record may be undertaken if deemed appropriate or necessary to adequately adjudicate the merits of the claim. A substitute claimant may submit additional evidence in support of the claim. In addition, VA is responsible for obtaining any additional evidence required and addressing notice or due process defects in the same manner as if the original claimant were still alive. Unlike accrued benefits claims, the record is not closed on the date of death of the original claimant, but rather, it remains open for the submission and development of any pertinent additional evidence for substituted claimants. Thus, it is to the Appellant's benefit to have the claim adjudicated as a substitute claimant pursuant to the newly enacted 38 U.S.C.A. § 5121A, rather than as the RO adjudicated them pursuant to 38 U.S.C.A. § 5121. Therefore, any eligible survivor submitting a claim for accrued benefits will be considered as requesting to substitute and may be able to submit additional evidence in support of the claim. The Board recharacterized the issue on appeal. This appeal was processed using the Veterans Benefits Management System (VBMS) paperless claims processing system. Accordingly, any future consideration of this Appellant's case should take into consideration the existence of this electronic record. In addition to the VBMS claims file, there is a Virtual VA paperless file associated with the claim. This appeal has been advanced on the Board's docket pursuant to 38 C.F.R. § 20.900(c) (2015). 38 U.S.C.A. § 7107(a)(2) (West 2014). FINDINGS OF FACT 1. The Veteran's G6PD is a congenital disease, and clear and unmistakable evidence establishes that such existed prior to service and did not permanently increase in severity beyond the natural progression during service. 2. As the Veteran has been granted a 100 percent rating for non-small cell lung cancer from January 21, 2009, the date of the original claim, and it is his sole service-connected disability, the issue of entitlement to TDIU is moot. CONCLUSIONS OF LAW 1. The criteria for service connection for G6PD are not met. 38 U.S.C.A. §§ 1111, 1131, 1153 (West 2014); 38 C.F.R. §§ 3.303, 3.306 (2015). 2. The appeal as to entitlement to TDIU is moot. 38 U.S.C.A. § 7105 (West 2014); 38 C.F.R. § 4.16 (2015). REASONS AND BASES FOR FINDING AND CONCLUSIONS I. Veterans Claims Assistance Act of 2000 The Veterans Claims Assistance Act of 2000 (VCAA), Pub. L. No. 106-475, 114 Stat. 2096 (Nov. 9, 2000) (codified at 38 U.S.C. §§ 5100, 5102, 5103, 5103A, 5106, 5107, and 5126 (West 2014)) redefined VA's duty to assist a claimant in the development of a claim. VA regulations for the implantation of the VCAA were codified as amended at 38 C.F.R. §§ 3.102, 3.156(a), 3.159, and 3.326(a) (2015). The notice requirements of the VCAA require VA to notify the claimant of any evidence that is necessary to substantiate the claim, as well as the evidence VA will attempt to obtain and which evidence he is responsible for providing. 38 C.F.R. § 3.159(b) (2015). The requirements apply to all five elements of a service connection claim: veteran status, existence of a disability, a connection between a veteran's service and the disability, degree of disability, and effective date of disability. Dingess v. Nicholson, 19 Vet. App. 473 (2006). VCAA notice must be provided to a claimant before the initial unfavorable decision on a claim for VA benefits by the agency of original jurisdiction (in this case, the RO). Id.; see also Pelegrini v. Prinicipi, 18 Vet. App. 112 (2004). However, the VCAA notice requirements may be satisfied if any errors in the timing or content of such notice are not prejudicial to the claimant. See Pelegrini, 18 Vet. App. at 121. The RO provided pre-adjudication VCAA notice by a letter dated in June 2009, prior to the Veteran's death. The notice included the types of evidence needed to substantiate the underlying claims of service connection, namely, evidence of an injury or disease or event, causing an injury or disease, during service; evidence of a current disability; and evidence of a relationship between the current disability and the injury or disease or event, causing the injury or disease, during service. The notice identified the evidence needed to substantiate a claim and the relative duties of VA and the Veteran to obtain evidence. The Veteran was notified of what information and evidence he needed to submitted and of what information and evidence would be obtained by VA. The notice included the provisions for the effective date of a claim and for the degree of disability assignable. This letter was provided to the Veteran prior to the adjudication of his claims, and therefore met the timing requirement. Additionally, the RO substantially complied with prior remand instructions. The instructions pertinent to deciding the claims included obtaining a VA opinion concerning whether the Veteran's G6PD deficiency was a congenital disease or defect, and whether, if the deficiency was determined to be a disease, whether it was aggravated by exposure to asbestos and/or fuel during service. Opinions concerning these inquiries were obtained in June 2015 and December 2015. Accordingly, the Board finds that there has been substantial compliance with the prior remand instructions and no further action is necessary. See D'Aries v. Peake, 22 Vet. App. 97 (2008) (holding that only substantial, and not strict, compliance with the terms of a Board remand is required pursuant to Stegall v. West, 11 Vet. App. 268 (1998)). VA must make reasonable efforts to assist the claimant in obtaining evidence necessary to substantiate the claim. The RO has obtained service treatment records and VA records, and obtained VA medical opinions. The VA opinion reports included a review of the Veteran's medical history, including his service treatment records, a review of the claims file, and a discussion of relevant medical treatises to determine that the Veteran's G6PD deficiency was a congenital disease that was not aggravated by service, to include exposures to asbestos and fuel therein. Therefore, the Board concludes that the VA opinions are adequate. 38 C.F.R. § 4.2 (2015); see Barr v. Nicholson, 21 Vet. App. 303, 312 (2007) (holding that when VA undertakes to provide an examination or obtain a VA opinion, it must ensure that examination or opinion is adequate). In summary, the duties imposed by the VCAA have been considered and satisfied. Through various notices of the RO/AMC, the Veteran has been notified and made aware of the evidence needed to substantiate this claim, the avenues through which he might obtain such evidence, and the allocation of responsibilities between himself and VA in obtaining such evidence. There is no additional notice that should be provided, nor is there any indication that there is additional existing evidence to obtain or development required to create any additional evidence to be considered in connection with the claim. Consequently, any error in the sequence of events or content of the notice is not shown to prejudice the Veteran or to have any effect on the appeal. Any such error is deemed harmless and does not preclude appellate consideration of the matter herein decided, at this juncture. See Mayfield v. Nicholson, 20 Vet. App. 539, 543 (2006) (rejecting the argument that the Board lacks authority to consider harmless error). See also ATD Corp. v. Lydall, Inc., 159 F.3d 534, 549 (Fed. Cir. 1998). II. Entitlement to Service Connection for G6PD deficiency The Appellant seeks entitlement to service connection for the Veteran's G6PD deficiency. The Appellant asserts that the Veteran's G6PD deficiency was due to exposure to asbestos and fuel during service. Service connection will be granted if the evidence demonstrates that a current disability resulted from an injury or disease incurred in or aggravated by active military service. 38 U.S.C.A. § 1110; 38 C.F.R. § 3.303(a). Establishing service connection generally requires (1) medical evidence of a current disability; (2) medical or, in certain circumstances, lay evidence of in-service incurrence or aggravation of a disease or injury; and (3) medical evidence of a nexus between the claimed in-service disease or injury and the present disability. Shedden v. Principi, 381 F.3d 1163, 1167 (Fed. Cir. 2004); see Caluza v. Brown, 7 Vet. App. 498, 506 (1995), aff'd per curiam, 78 F.3d 604 (Fed.Cir.1996) (table); Hickson v. West, 12 Vet. App. 247, 253 (1999); 38 C.F.R. § 3.303. Every Veteran shall be taken to have been in sound condition when examined, accepted, and enrolled for service, except as to defects, infirmities, or disorders noted at the time of the examination, acceptance, and enrollment, or where clear and unmistakable evidence demonstrates that the injury or disease existed before acceptance and enrollment and was not aggravated by such service. See 38 U.S.C.A. §§ 1111; 38 C.F.R. § 3.304(b). Only such conditions as are recorded in examination reports are to be considered as noted. 38 C.F.R. § 3.304(b). If a condition is not noted upon entrance into service, then to rebut the presumption of soundness at service entrance VA must show by clear and unmistakable evidence both that there was a pre-existing condition and that it was not aggravated during or by the Veteran's service. Wagner v. Principi, 370 F.3d 1089 (Fed. Cir. 2004); VAOPGCPREC 3-2003 (July 16, 2003). To satisfy this second-prong requirement for rebutting the presumption of soundness, the government must show by clear and unmistakable evidence either that there was no increase in disability during service or that any increase in disability was "due to the natural progression" of the condition. Joyce v. Nicholson, 443 F.3d 845, 847 (Fed. Cir. 2006). If a pre-existing disability is noted upon entry into service, then the Veteran cannot bring a claim for service connection for that disability, only a claim for service-connected aggravation of that disability. In that case, 38 U.S.C.A. § 1153 applies and the burden falls on him, not VA to establish aggravation. Wagner, 370 F.3d at 1096; Jensen v. Brown, 19 F.3d 1413, 1417 (Fed. Cir. 1994); 38 C.F.R. § 3.306. Defects are defined as "structural or inherent abnormalities or conditions which are more or less stationary in nature." VAOPGCPREC 82-90 (July 18, 1990). Congenital or developmental "defects" automatically rebut the presumption of soundness and are therefore considered to have pre-existed service. 38 C.F.R. §§ 3.303(c), 4.9. Service connection is generally precluded by regulation for such "defects", because they are not "diseases" or "injuries" within the meaning of applicable legislation. 38 C.F.R. §§ 3.303(c), 4.9, 4.127; accord Terry v. Principi, 340 F.3d 1378, 1383-84 (Fed. Cir. 2003); Palczewski v. Nicholson, 21 Vet. App. 174, 179 (2007). VA's Office of General Counsel has distinguished between congenital or developmental defects, for which service connection is precluded by regulation, and congenital or hereditary diseases, for which service connection may be granted, if initially manifested in or aggravated by service. See VAOPGCPREC 82-90, VAOPGCPREC 67-90. The VA General Counsel draws on medical authorities and case law from other federal jurisdictions and concludes that a defect differs from a disease in that a defect is "more or less stationary in nature", while a disease is "capable of improving or deteriorating." See VAOPGCPREC 82-90 at para. 2. In this regard, the presumption of soundness does not apply to congenital defects because such defects "are not diseases or injuries" within the meaning of 38 U.S.C.A. §§ 1110 and 1111. See 38 C.F.R. § 3.303(c); see also Quirin, 22 Vet. App. at 397; Terry, 340 F.3d at 1385-86 (holding that the presumption of soundness does not apply to congenital defects); Winn v. Brown, 8 Vet. App. 510, 516 (1996) (holding that a non-disease or non-injury entity such as a congenital defect is "not the type of disease- or injury-related defect to which the presumption of soundness can apply"). However, a congenital defect can still be subject to superimposed disease or injury. VAOPGCPREC 82-90. If such superimposed disease or injury does occur, service connection may be warranted for the resulting disability. Id. However, if it is determined during service that a Veteran suffers from a congenital disease, as opposed to a defect, VA cannot simply assume that, because of its congenital nature, the disease must have preexisted service. That is, the presumption of soundness still applies to congenital diseases that are not noted at entry. Quirin, 22 Vet. App. at 396-397. Since the presumption of soundness at entrance attaches, VA must show by clear and unmistakable evidence that the congenital disease preexisted service. Monroe v. Brown, 4 Vet. App. 513, 515 (1993). VA may not rely on a regulation as a substitute for the requirement that it rely on independent medical evidence. Colvin v. Derwinski, 1 Vet. App. 171, 175 (1991). VA's Office of General Counsel has also confirmed that the existence of a congenital hereditary disease under 38 C.F.R. § 3.303(c) does not always rebut the presumption of soundness, and that service connection may be granted for congenital hereditary diseases which either first manifest themselves during service or which preexist service and progressed at an abnormally high rate during service. See VAOPGCPREC 67-90; 55 Fed. Reg. 43,253 (1990). In short, service connection is available for congenital diseases, but not defects, that are aggravated in service. Quirin, 22 Vet. App. at 394; Monroe v. Brown, 4 Vet. App. 513, 515 (1993). In cases where the appellant seeks service connection for a congenital condition, the Board must indicate whether the condition is a disease or defect and discuss the presumption of soundness. Quirin, 22 Vet. App. at 394-397. It follows that in such cases where a congenital condition is at issue, a VA medical opinion may be needed to determine whether the condition is a disease or defect, whether the presumption of soundness has been rebutted, and if so whether there was aggravation during service. Id. at 395. In cases involving asbestos exposure, the claim must be analyzed under VA administrative protocols. Ennis v. Brown, 4 Vet. App. 523 (1993); McGinty v. Brown, 4 Vet. App. 428 (1993). Although there is no specific statutory or regulatory guidance regarding claims for residuals of asbestos exposure, VA has several guidelines for compensation claims based on asbestos exposure. See M21-1, VBA Adjudication Procedure Manual M21-1 Manual Rewrite (M21-1 MR), Part IV, Subpart ii, Ch. 2, Section C, Topic 9 and Section H, Topic 29 (Dec. 13, 2005). Additionally, the Board must follow development procedures specifically applicable to asbestos-related claims. Ashford v. Brown, 10 Vet. App. 120, 124-125 (1997). VA must determine whether military records demonstrate evidence of asbestos exposure during service, whether there was pre-service and/or post-service occupational or other asbestos exposure, and whether there is a relationship between asbestos exposure and the claimed disease. As an initial matter, the Veteran was diagnosed with G6PD deficiency and the first element of service connection is met. As for the second requirement for service connection, that a disease or injury was incurred or aggravated during service, the Board notes that the Veteran's personnel records indicate that he served in the Navy as a boatswain's mate. As such, exposure to asbestos and fuel has been conceded. The Veteran's service treatment records show that in August 1976 the Veteran was tested for G6PD deficiency, and was found to have a negative test, revealing a deficient amount of the enzyme. Service treatment records show that the Veteran was seen for acute gastroenteritis in December 1976 and January 1977; he sought treatment for an upper respiratory infection in February 1977; in June 1977 he was seen for a mild infection due to improper circumcision; in July 1977 he was treated for a sore throat; in November 1977 he was treated for urethral discharge; he was seen in June 1978 for a laceration to the hand and for trauma to the right hand; he was treated in November 1978 for swollen left eye; and he was seen for situational reaction in February 1979. In his report of medical history from June 1979, the Veteran endorsed dizziness or fainting spells and the physician explained that the Veteran had frequent dizziness when standing up. During his June 1979 separation examination, the clinical examination was normal. In his claim of entitlement to service connection, the Veteran asserted that he was given the diagnosis of G6PD deficiency while he was on the USS Constellation ship and he underwent an adult circumcision. The Veteran also stated that he worked in the paint locker where he mixed different paints; he also reported that he painted and chipped paint. He stated that the paint he was exposed to was red lead, zinc oxide, and 117, which were all primers. He also reported that he used haze gray and deck gray, which he described as Navy regulation. He stated that breathing in the fumes form the various paints plus his exposure to asbestos dust both on the ship and in the shipyard aggravated his G6PD condition. He stated that, after service, he continued to suffer form an anemic condition; he reported that he noticed shortness of breath and that the condition worsened and caused him to seek medical treatment in December 2008. In an October 2009 statement, the Appellant asserted that the Veteran's G6PD condition was aggravated by exposure to asbestos and fuels. She indicated that the Veteran had been treated for anemia on several occasions, which she believed was related to the G6PD deficiency. She stated that the Veteran's job description listed painting as a job performed by a boatswain's mate, and that the loose paint had a high chance of containing asbestos. The Board recognizes that several buddy statements have been received in March 2009 and November 2014 attesting to the fact that the Veteran was provided red "dog tags" in service denoting his condition. However, as the Board concedes the Veteran's diagnosis of G6PD deficiency, this evidence is not relevant for the issue of determining whether the G6PD deficiency was aggravated by the Veteran's service. A VA opinion was provided in June 2011. The examiner reviewed the claims file and noted that the Veteran was tested for G6PD in August 1976 and was found to have a negative test. The examiner noted that G6PD deficiency is an x-linked recessive hereditary condition characterized by abnormally low levels of G6PD, a metabolic enzyme involved in the pentose phosphate pathway, especially important in red blood cell metabolism. The examiner noted that the G6PD deficiency is the most common human enzyme defect. The examiner opined that, based on the medical literature, the Veteran suffered from the G6PD congenital defect. A medical opinion was obtained in April 2015. The examiner opined that the Veteran's G6PD deficiency was a congenital disease. The examiner explained that it is a genetic disorder that occurs most often in males. The examiner stated that the Veteran's G6PD deficiency was not incurred in or otherwise etiologically related to active military service to include exposure to asbestos and fuel during service. The examiner stated that the disease, which was not noted upon entrance into service, clearly and unmistakably (obviously or manifestly) existed prior to the Veteran's entry to service, because it was a congenital disease and had existed since birth. The examiner found that the Veteran's G6PD deficiency was not aggravated by military service. The examiner then explained that it is transmitted as x-linked genetic disorder, generally from mother to son. When red blood cells are exposed to oxidative stress, the cell membrane either bursts or is damaged because there is not enough glutation to protect it. He explained that the disease can be controlled, not cured. The examiner noted that there was no evidence in the service medical records that the G6PD deficiency was aggravated during service. In June 2015, another opinion was provided. The examiner noted that the Veteran's G6PD deficiency is a congenital disease. The examiner clarified that the G6PD deficiency is caused by a defect in an enzyme, but that this disease fits the definition of a congenital disease and not a congenital defect. The examiner stated that by virtue of the disease being congenital, it existed at birth, thus was present prior to the Veteran's entry into active duty. The examiner stated that there was no documented evidence that the disorder was aggravated by military service. The examiner noted that asbestos is not listed as one of the chemicals that are known to cause an exacerbation of G6PD deficiency. In summary, the examiner explained that G6PD deficiency is an X-linked congenital disease that is manifested mostly in males and that patients with this deficiency have a broad range of symptoms which include chronic anemia to no symptoms at all. In general, she noted that if there are symptoms, the symptoms are usually related to an acute hemolytic anemia that occurs within a few days after exposure to a medication or chemical (of which, asbestos is not listed) known to cause oxidative stress on red blood cells that are deficient in the enzyme that is affected by G6PD deficiency which results in the lysis (breaking open) of red blood cells making the patient anemic (low red blood cell or hemoglobin level). This is, she explained, usually a self-limiting process, meaning the hemolytic anemia stops on its own after removal of the offending agent. She explained that there is no specific treatment except to avoid offending agents known to cause hemolytic anemia in these patients and supportive care (red blood cell transfusions), if needed, while the patient recovers. The examiner noted that most patients with this disease do not have chronic anemia or chronic symptoms that could be attributed to G6PD deficiency, provided they are not chronically exposed to offending agents. She noted that there was no mention in the records available to her of the Veteran ever having anemia or a hemolytic anemia exacerbation. She stated that there is no known relationship between G6PD deficiency and lung cancer, and it was not mentioned in any notes available to her from the Veteran's treating oncologist that his G6PD was or could have been a factor in his death. The examiner noted that the Veteran mentioned that he had anemia, and that she had not found that information in the records that were available, but that would not change her opinions. She stated that anemia would be an expected finding of this disease, as mentioned above, and would be part of the natural course of this disease. Another medical opinion was provided in December 2015. The examiner reviewed the records and the electronic claims file. The examiner opined that the Veteran's G6PD was clearly and unmistakably not aggravated by exposure to fuel during service. The examiner stated that "fuel" is not a chemical known to be unsafe in patients with G6PD deficiency. The examiner referenced a medical treatise regarding a list of drugs and chemicals that are likely to be unsafe in G6PD deficiency. The examiner further explained that the medical literature did not support fuel as a known aggravator of G6PD. As noted above, generally, service connection for congenital "disease" may be service-connected if incurred or aggravated during service within the meaning of VA law and regulations. VAOPGCPREC 82-90 (July 18, 1990). As G6PD is a disease entity and not a "defect," the presumption of soundness under 38 U.S.C.A. § 1111 is applicable. Quirin v. Shinseki, 22 Vet. App. 390, 396-97 (2009). In this case, the Veteran's G6PD deficiency was noted on bloodwork that was completed after his entrance to service in August 1976. According to the April 2015 VA medical opinion, G6PD is a congenital disease, and the examiner found that the record clearly and unmistakably establishes that the Veteran's G6PD existed prior to service. Thus, VA has the burden of establishing by clear and unmistakable evidence that G6PD was not aggravated during service. Wagner v. Principi, 370 F. 3d 1089, 1096 (2004). A pre-existing injury or disease will be considered to have been aggravated during service where there is an increase in disability during service unless there is a specific finding that the increase in disability is due to the natural progress of the disease. 38 U.S.C.A. § 1153. However, aggravation of a pre-existing injury or disease will not be conceded where the disability underwent no increase in severity during service on the basis of all the evidence of record pertaining to the manifestations of the disability prior to, during and subsequent to service. 38 C.F.R. § 3.306. Temporary or intermittent flare-ups of symptoms of a condition, alone, do not constitute sufficient evidence aggravation unless the underlying condition worsened. Davis v. Principi, 276 F. 3d 1341, 1346-47 (Fed. Cir. 2002); Hunt v. Derwinski, 1 Vet. App. 292, 297 (1991). In Wagner, the Federal Circuit, as relevant to the aggravation prong, found that the government may show a lack of aggravation by establishing that there was no increase in disability during service or that any "increase in disability [was] due to the natural progress" of the preexisting condition. Id. at 1096. The term "clear and unmistakable evidence," as used in 38 U.S.C.A. § 1111, has been defined as evidence that "cannot be misinterpreted and misunderstood, i.e., it is undebatable." Vanerson v. West, 12 Vet. App. 254, 258-59 (1999) (citing the definition of "clear and unmistakable error" in Russell v. Principi, 3 Vet. App. 310, 313-14 (1992) (en banc). With respect to the factor of aggravation of G6PD deficiency, the Veteran's service treatment records reflect no lay or medical evidence of his claimed G6PD symptoms during service. He sought treatment for several ailments and complaints, including acute gastroenteritis, an upper respiratory infection, a mild infection due to improper circumcision, a sore throat, urethral discharge, a laceration to the hand and for trauma to the right hand, a swollen left eye, and a situational reaction. In his report of medical history from June 1979, the Veteran endorsed dizziness when standing up. As such, the evidence does not show, and the Veteran and the Appellant have not contended, that the Veteran experienced symptoms he attributed to his G6PD deficiency. Moreover, the June 2011, April 2015, June 2015, and December 2015 VA examiners collectively found that the Veteran's G6PD deficiency clearly and unmistakably preexisted service and clearly and unmistakably was not aggravated by service, to include any exposures therein. The probative value of medical opinion evidence is based on the medical experts' personal examination of the evidence, their knowledge and skill in analyzing the data, and their medical conclusions. As is true with any piece of evidence, the credibility and weight to be attached to these opinions are within the province of the adjudicator. Guerrieri v. Brown, 4 Vet. App. 467, 470-71 (1993). Whether a physician provides a basis for his or her medical opinion goes to the weight or credibility of the evidence in the adjudication of the merits. See Hernandez-Toyens v. West, 11 Vet. App. 379, 382 (1998). Other factors for assessing the probative value of a medical opinion are the physician's access to the claims folder and the thoroughness and detail of the opinion. See Nieves-Rodriguez, 22 Vet. App. 295 (2008); Prejean v. West, 13 Vet. App. 444, 448-9 (2000). The Board finds the April 2015, June 2015, and August 2015 VA examiners' opinions to be highly probative. The June 2015 examiner opined that there was no documented evidence that the disorder was aggravated by military service, and explained that asbestos is not listed as one of the chemicals that is known to cause an exacerbation of G6PD deficiency. The December 2015 examiner opined that the Veteran's G6PD was clearly and unmistakably not aggravated by exposure to fuel during service. The examiner stated that "fuel" is not a chemical known to be unsafe in patients with G6PD deficiency. The examiner referenced a medical treatise regarding a list of drugs and chemicals that are likely to be unsafe in G6PD deficiency. The examiner further explained that the medical literature did not support fuel as a known aggravator of G6PD. The Board recognizes that the examiners did not specifically discuss the Veteran's lay statements or the statements by the Appellant during the course of the examination report. However, the examiners explicitly noted that they had reviewed the entire claims file, which included these statements. Further, the examiners provided specific opinions that the Veteran's G6PD deficiency was not aggravated by the chemicals that the Veteran and the Appellant identified he had been exposed to. Thus, while the examiners may not have specifically discussed the precise way in which they reached his conclusion, including their review of the lay evidence, it is clear from the thorough review of the claims file that the examiners relied on the relevant information as well as their medical knowledge and expertise and medical treatise information to draw their conclusions and reach their opinions. Given the examiners' consideration of the medical records and lay statements, unequivocal and conclusive opinions, and clear reasoning for the conclusions, the Board finds the examiners' opinion to be highly probative in determining that the Veteran's G6PD deficiency clearly and unmistakably preexisted service and clearly and unmistakably was not aggravated by service. See Nieves-Rodriguez, 22 Vet. App. 295 (2008); Stefl v. Nicholson, 21 Vet. App. 120, 124 (2007). Overall, the probative evidence clearly and unmistakably establishes that the Veteran's pre-existing G6PD did not increase in severity in service beyond its normal progression during service. There is no indication that the Veteran suffered from any symptoms from his G6PD deficiency during service. Service treatment records show no complaints of or treatment for any complaints related to his G6PD deficiency. To the extent that the Appellant argues otherwise, the Board places greater probative value on the opinions of the VA examiners who have greater expertise and training than the Veteran in identifying the disease characteristics of G6PD. As to the aggravation of G6PD and the relationship of his exposure to asbestos, fuel, and paint in service to such disease, the Board finds such subject matters to be complex in nature and beyond the competence of a lay person, to include the Veteran and the appellant. See Woehlaert v. Nicholson, 21 Vet. App. 456 (2007) (although the claimant is competent in certain situations to provide a diagnosis of a simple condition such as a broken leg or varicose veins, the claimant is not competent to provide evidence as to more complex medical questions). The persuasive value of their lay contentions is low because the overall factual picture is complex. Given the lack of complaints attributed or attributable to his G6PD deficiency during service and the normal clinical evaluation at separation, and the complex nature of the particular disorder at issue, the Board finds that the Veteran and the Appellant's lay statements are insufficient to provide a nexus between the Veteran's alleged aggravation of G6PD deficiency and his active duty service. Thus, the Board accords the Veteran's and the Appellant's statements regarding the aggravation of his G6PD deficiency and the relationship between his G6PD deficiency and his exposure to asbestos and fuel little probative value as neither has been shown to be competent to opine on such complex medical questions. Specifically, where the determinative issue is one of medical causation, only those with specialized medical knowledge, training, or experience are competent to provide evidence on the issue. See Jones v. Brown, 7 Vet. App. 134, 137 (1994). Additionally, as previously stated, the opinions of the June 2011, April 2015, June 2015, and December 2015 VA examiners who have the necessary training and medical knowledge to competently speak to the issues at hand are highly probative. For the reasons and bases discussed above, the Board concludes that the presumption of soundness is rebutted by clear and unmistakable evidence demonstrating that the Veteran's G6PD deficiency, which is a congenital disease, preexisted service and was not aggravated by such service. Accordingly, service connection for a G6PD deficiency is denied. See Wagner v. Principi, supra. III. TDIU The Veteran filed a claim of entitlement to TDIU in May 2009. In a July 2015 decision, the Board granted service connection for non-small cell lung cancer, which was effectuated by an August 2015 rating decision. The RO assigned a 100 percent rating effective January 21, 2009, the date of the Veteran's original claim. The United States Court of Appeals for Veterans Claims (Court) has recognized that a 100 percent rating under the Schedule for Rating Disabilities means that a Veteran is totally disabled. Holland v. Brown, 6 Vet. App. 443, 446 (1994), citing Swan v. Derwinski, 1 Vet. App. 20, 22 (1990). Thus, if VA has found a Veteran to be totally disabled as a result of a particular service-connected disability or combination of disabilities pursuant to the rating schedule, there is no need, and no authority, to otherwise rate that Veteran totally disabled on any other basis. See Herlehy v. Principi, 15 Vet. App. 33, 35 (2001) (finding a request for TDIU moot where 100 percent schedular rating was awarded for the same period). However, a grant of a 100 percent disability does not always render the issue of TDIU moot. As is potentially relevant here, VA's duty to maximize a claimant's benefits includes consideration of whether his disabilities establishes entitlement to special monthly compensation (SMC) under 38 U.S.C.A. § 1114. See Buie v. Shinseki, 24 Vet. App. 242, 250 (2011); Bradley v. Peake, 22 Vet. App. 280, 294 (2008). Specifically, SMC may be warranted if the Veteran has a 100 percent disability rating for a single disability, and VA finds that TDIU is warranted based solely on the disabilities other than the disability that is rated at 100 percent. See Bradley, 22 Vet. App. 280 (analyzing 38 U.S.C.A. § 1114(s)); See also 75 Fed. Reg. 11,229-04 (March 10, 2010) (withdrawing VAOPGCPREC 6-1999). The current case is distinguishable from Bradley in that the only service-connected disability is non-small cell lung cancer, which has been assigned a 100 percent evaluation, effective January 21, 2009, the date of the original claim. Additionally, the Board denied service connection for G6PD deficiency. As such, a separate award of TDIU benefits cannot be granted in addition to the already awarded 100 percent evaluation for non-small cell lung cancer, as it is the only service-connected disability. And, the 100 percent rating has been effectuated for the entire appeal period. Thus, the requirements under 38 U.S.C.A. § 1114(s) are not met and further consideration of a TDIU rating for special monthly compensation purposes is not warranted. See Bradley v. Peake, 22 Vet. App. 280, 292 (2008). The issue of entitlement to TDIU is moot. ORDER Entitlement to service connection for G6PD deficiency, for substitution and accrued benefits purposes is denied Entitlement to TDIU is dismissed. ____________________________________________ DEBORAH W. SINGLETON Veterans Law Judge, Board of Veterans' Appeals Department of Veterans Affairs