2-methylbutyryl-CoA dehydrogenase deficiency associated with autism and mental retardation: a case report.
BACKGROUND
2-methylbutyryl-CoA dehydrogenase deficiency or short/branched chain acyl-CoA dehydrogenase deficiency (SBCADD) is caused by a defect in the degradation pathway of the amino acid L-isoleucine.


METHODS
We report a four-year-old mentally retarded Somali boy with autism and a history of seizures, who was found to excrete increased amounts of 2-methylbutyryl glycine in the urine. The SBCAD gene was examined with sequence analysis. His development was assessed with psychometric testing before and after a trial with low protein diet.


RESULTS
We found homozygosity for A > G changing the +3 position of intron 3 (c.303+3A > G) in the SBCAD gene. Psychometric testing showed moderate mental retardation and behavioral scores within the autistic spectrum. No beneficial effect was detected after 5 months with a low protein diet.


CONCLUSIONS
This mutation was also found in two previously reported cases with SBCADD, both originating from Somalia and Eritrea, indicating that it is relatively prevalent in this population. Autism has not previously been described with mutations in this gene, thus expanding the clinical spectrum of SBCADD.
Kanavin
Oivind J
OJ
Department of Pediatrics, Ullevål University Hospital, Oslo, Norway. oivind.kanavin@ulleval.no.
Woldseth
Berit
B
Jellum
Egil
E
Tvedt
Bjorn
B
Andresen
Brage S
BS
Stromme
Petter
P