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Short/Branched Chain Acyl-CoA Dehydrogenase (SBCAD) Deficiency
ACADSB gene
Short/branched chain acyl-CoA dehydrogenase (SBCAD) deficiency also known as 2-methylbutyryl-CoA dehydrogenase deficiency is a rare autosomal recessive disorder of isoleucine metabolism. The clinical spectrum of this disorder has not been clearly defined as few patients with SBCAD deficiency have been described. Very few symptomatic patients have been reported. Several symptomatic patients presented with acute crisis in the newborn period including lethargy, poor feeding, apnea, hypothermia, hypoglycemia, EEG and MRI abnormalities, convulsions, lactic acidosis, respiratory distress, seizures, sepsis, disseminated intravascular coagulation and cerebral hemorrhage. Another group of symptomatic patients presented after the neonatal period with symptoms that include hypotonia, motor delay, strabismus, apnea, infantile spasms, developmental delay, attention deficit hyperactivity disorder, recurrent vomiting and failure to thrive. A mother of one of the affected patients was also diagnosed with SBCAD deficiency but is healthy. Most patients have been diagnosed following positive newborn screening result for C5 elevation or were identified after the diagnosis of SBCAD in a sibling. These individuals have remained healthy, most with little or no treatment. There have been only a few small studies of patients with SBCAD deficiency. In 6 of these studies (total of 18 patients), sequencing genomic DNA identified ACADSB mutations on 33/36 alleles (92%).
Mutation analysis of the ACADSB gene is performed on genomic DNA from the submitted specimen using bi-directional sequence analysis of coding exons and corresponding intron/exon boundaries. For individuals of Hmong descent, mutation specific testing for the M389V mutation is offered as a separate test. If full sequencing identifies a mutation on only one allele of the ACADSB gene, and if clinically indicated, reflex deletion/duplication testing (ExonArrayDx) will be performed at no additional charge to evaluate for a deletion/duplication of one or more exons of this gene. Mutations found in the first person of a family to be tested are confirmed by repeat analysis using sequencing, restriction fragment analysis or another appropriate method.
Information Sheet, including prices and CPT codes
Consent Document
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options
2-methylbutyryl-CoA dehydrogenase deficiency, SBCAD, 2-METHYLBUTYRYL GLYCINURIA, SBCADD, 2-methylbutyryglycine, C5, 2-methylbutyrylcarnitine
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