{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T10:04:30Z","timestamp":1784714670759,"version":"3.55.0"},"reference-count":39,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2019,6,13]],"date-time":"2019-06-13T00:00:00Z","timestamp":1560384000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Brain Sciences"],"abstract":"<jats:p>Systemic primary carnitine deficiency (PCD) is a genetic disorder caused by decreased or absent organic cation transporter type 2 (OCTN2) carnitine transporter activity, resulting in low serum carnitine levels and decreased carnitine accumulation inside cells. In early life, PCD is usually diagnosed as a metabolic decompensation, presenting as hypoketotic hypoglycemia, Reye syndrome, or sudden infant death; in childhood, PCD presents with skeletal or cardiac myopathy. However, the clinical presentation of PCD characterized by autism spectrum disorder (ASD) with intellectual disability (ID) has seldom been reported in the literature. In this report, we describe the clinical features of a seven-year-old girl diagnosed with PCD who presented atypical features of the disease, including a developmental delay involving language skills, concentration, and attention span, as well as autistic features and brain alterations apparent in magnetic resonance imaging. We aim to highlight the difficulties related to the diagnostic and therapeutic approaches used to diagnose such patients. The case reported here presented typical signs of PCD, including frequent episodes of hypoglycemia, generalized muscle weakness, decreased muscle mass, and physical growth deficits. A molecular genetic study confirmed the definitive diagnosis of the disease (c.1345T&gt;G (p.Y449D)) in gene SLC22A5, located in exon 8. PCD can be accompanied by less common clinical signs, which may delay its diagnosis because the resulting global clinical picture can closely resemble other metabolic disorders. In this case, the patient was prescribed a carnitine-enriched diet, as well as oral carnitine at a dose of 100 mg\/kg\/day. PCD has a better prognosis if it is diagnosed and treated early; however, a high level of clinical suspicion is required for its timely and accurate diagnosis.<\/jats:p>","DOI":"10.3390\/brainsci9060137","type":"journal-article","created":{"date-parts":[[2019,6,13]],"date-time":"2019-06-13T11:15:58Z","timestamp":1560424558000},"page":"137","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["First Case Report of Primary Carnitine Deficiency Manifested as Intellectual Disability and Autism Spectrum Disorder"],"prefix":"10.3390","volume":"9","author":[{"given":"Jos\u00e9","family":"Guevara-Campos","sequence":"first","affiliation":[{"name":"\u201cFelipe Guevara Rojas\u201d Hospital, Pediatrics Service, University of Oriente, El Tigre-Anzo\u00e1tegui 6034, Venezuela"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Luc\u00eda","family":"Gonz\u00e1lez-Guevara","sequence":"additional","affiliation":[{"name":"\u201cFelipe Guevara Rojas\u201d Hospital, Epilepsy and Encephalography Unit, El Tigre-Anzo\u00e1tegui 6034, Venezuela"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jos\u00e9","family":"Guevara-Gonz\u00e1lez","sequence":"additional","affiliation":[{"name":"\u201cMiguel P\u00e9rez Carre\u00f1o\u201d Hospital, Pediatrics Service, Caracas 1020, Venezuela"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5669-4943","authenticated-orcid":false,"given":"Omar","family":"Cauli","sequence":"additional","affiliation":[{"name":"Department of Nursing, University of Valencia, 46010 Valencia, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,6,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1093\/hmg\/8.4.655","article-title":"Mutations of OCTN2, an Organic Cation\/Carnitine Transporter, Lead to Deficient Cellular Carnitine Uptake in Primary Carnitine Deficiency","volume":"8","author":"Tang","year":"1999","journal-title":"Hum. 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