{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T12:25:54Z","timestamp":1777379154716,"version":"3.51.4"},"reference-count":38,"publisher":"American Academy of Pediatrics (AAP)","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2012,6,1]]},"abstract":"<jats:sec>\n                  <jats:title>OBJECTIVE:<\/jats:title>\n                  <jats:p>Methylmalonic acidemia (MMA) is a metabolic disorder with a poorly defined long-term neurocognitive phenotype. We studied the neuropsychological outcomes of patients and examined clinical covariates that influenced cognition.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>METHODS:<\/jats:title>\n                  <jats:p>A diverse cohort with mut, cblA, or cblB subtypes of isolated MMA (N = 43), ages 2 to 32 years, were evaluated at a single center over a 6-year period. The influence of clinical, laboratory, and metabolic parameters on neuropsychological testing results was determined.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>RESULTS:<\/jats:title>\n                  <jats:p>Early-onset mut patients (n = 21) manifested the most severe neurocognitive impairments, with a mean \u00b1 SD full-scale IQ (FSIQ) of 71.1 \u00b1 14.75. Late-onset mut patients (n = 6) had a mean FSIQ of 88.5 \u00b1 27.62. cblA (n = 7), cblB (n = 6), and mut patients diagnosed prenatally or by newborn screening (n = 3) obtained mean FSIQs in the average range (100.7 \u00b1 10.95, 96.6 \u00b1 10.92, and 106.7 \u00b1 6.66, respectively). Hyperammonemia at diagnosis and the presence of a seizure disorder were associated with a lower FSIQ (P = .001 and P = .041, respectively), but other clinical variables, including basal ganglia injury and mutation status, did not. FSIQ remained stable over longitudinal testing (n = 10). Decreased scores on processing speed, compared with all other intellectual domains, emerged as a specific neurocognitive manifestation.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>CONCLUSIONS:<\/jats:title>\n                  <jats:p>The neurocognitive outcomes seen in isolated MMA are highly variable. An earlier age of disease onset, the presence of hyperammonemia at diagnosis, and a history of seizures were associated with more severe impairment. In all patient subtypes, selective deficits in processing speed were present.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1542\/peds.2011-1715","type":"journal-article","created":{"date-parts":[[2012,5,22]],"date-time":"2012-05-22T00:21:46Z","timestamp":1337646106000},"page":"e1541-e1551","source":"Crossref","is-referenced-by-count":51,"title":["Neurocognitive Phenotype of Isolated Methylmalonic Acidemia"],"prefix":"10.1542","volume":"129","author":[{"given":"Colin J.","family":"O\u2019Shea","sequence":"first","affiliation":[{"name":"Office of the Clinical Director, National Institute of Mental Health,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jennifer L.","family":"Sloan","sequence":"additional","affiliation":[{"name":"Genetics and Molecular Biology Branch, National Human Genome Research Institute,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Edythe A.","family":"Wiggs","sequence":"additional","affiliation":[{"name":"Office of the Clinical Director, National Institute of Neurological Disorders and Stroke, and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maryland","family":"Pao","sequence":"additional","affiliation":[{"name":"Office of the Clinical Director, National Institute of Mental Health,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrea","family":"Gropman","sequence":"additional","affiliation":[{"name":"Genetics and Molecular Biology Branch, National Human Genome Research Institute,"},{"name":"Division of Neurology, Children\u2019s National Medical Center, Washington, District of Columbia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eva H.","family":"Baker","sequence":"additional","affiliation":[{"name":"Radiology and Imaging Sciences, National Institutes of Health, Bethesda, Maryland; and"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Irini","family":"Manoli","sequence":"additional","affiliation":[{"name":"Genetics and Molecular Biology Branch, National Human Genome Research Institute,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Charles P.","family":"Venditti","sequence":"additional","affiliation":[{"name":"Genetics and Molecular Biology Branch, National Human Genome Research Institute,"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Joseph","family":"Snow","sequence":"additional","affiliation":[{"name":"Office of the Clinical Director, National Institute of Mental Health,"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"417","published-online":{"date-parts":[[2012,6,1]]},"reference":[{"issue":"225","key":"2021120903360462600_B1","doi-asserted-by":"crossref","first-page":"492","DOI":"10.1136\/adc.42.225.492","article-title":"Methylmalonic aciduria. 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