title: 3-Methylcrotonyl-CoA carboxylase deficiency: phenotypic variability in a family.
abstract: A family with 3-methylcrotonyl-CoA carboxylase deficiency with different clinical features is described. A 15-month-old boy, who was the index patient, was admitted to the hospital with atonic seizure. His brother had delayed language development and their uncle had been followed with diagnosis of epilepsy for the last 5 years. Urinary organic acid analysis displayed elevated 3-hydroxyisovaleric acid and 3-methylcrotonylglycine, analysis of acylcarnitines showed elevated 3-hydroxyisovalerylcarnitine and decreased free carnitine levels in both the patients and their uncle. Methylcrotonyl-CoA carboxylase activity in cultured fibroblasts displayed a low residual activity of 2.2% of the median control value while propionyl-CoA carboxylase activity was normal in the index patient. Mutation analysis revealed a large homozygous deletion of 2264 bp (c.873+4524_6787de12264) in the MCCA gene, which has not been described to date. Adult-onset afebrile seizures have not been reported in the literature. Our cases are an example of this wide phenotypic variability within a single family.
authors.affiliation: Department of Pediatric Metabolism and Nutrition, Gazi University Hospital, 10. floor, Beşevler, Ankara, Turkey. tubaeminoglu@yahoo.com.tr
authors.forename: F Tuba
authors.initials: FT
authors.lastname: Eminoglu
authors.forename: Aysima A
authors.initials: AA
authors.lastname: Ozcelik
authors.forename: Ilyas
authors.initials: I
authors.lastname: Okur
authors.forename: Leyla
authors.initials: L
authors.lastname: Tumer
authors.forename: Gursel
authors.initials: G
authors.lastname: Biberoglu
authors.forename: Ercan
authors.initials: E
authors.lastname: Demir
authors.forename: Alev
authors.initials: A
authors.lastname: Hasanoglu
authors.forename: Matthias R
authors.initials: MR
authors.lastname: Baumgartner