Y chromosome mosaicism in the gonads, but not in the blood, of a girl with the Turner phenotype and virilized external genitalia.

We describe a girl with virilized external genitalia and phenotypic features of Turner syndrome whose blood karyotype is 45,X. The presence of dysgenetic testicular tissue was confirmed by pathology. Using PCR and primers for the distal long arm, centromere and short arm of the Y chromosome, Y chromosome material was detected in her gonads but not in blood.

Molecular genetic basis of maple syrup urine disease in a family with two defective alleles for branched chain acyltransferase and localization of the gene to human chromosome 1.

Maple syrup urine disease in humans results from inherited defects in branched chain alpha-ketoacid dehydrogenase, a mitochondrial multienzyme complex. A variety of genetic changes may produce this phenotype by affecting the function of any of the three complex-specific subunits. The varied clinical expression observed in patients may be partially explained by the defects in the involved subunit.

Reversion of the maple syrup urine disease phenotype of impaired branched chain alpha-ketoacid dehydrogenase complex activity in fibroblasts from an affected child.

Branched chain alpha-ketoacid dehydrogenase is a heteroprotein complex of mitochondria and commits the branched chain alpha-ketoacids to their catabolic fate. Inherited nuclear mutations in humans decrease the activity of this complex and result in maple syrup urine disease. Here we demonstrate the restoration of branched chain alpha-ketoacid dehydrogenase activity to fibroblasts from a child with this disorder by transfection with a cDNA for the prebranched chain acyltransferase.

Construction and nucleotide sequence of a cDNA encoding the full-length preprotein for human branched chain acyltransferase.

A cDNA (1.6 kilobases) for branched chain acyltransferase (E2b) isolated from a human liver library encoded only the amino-terminal half of the protein (Hummel, K. B.