The human steroidogenic acute regulatory (StAR) gene is expressed in the urogenital system and encodes a mitochondrial polypeptide.

The first enzymatic step in the biosynthesis of steroid hormones occurs in the mitochondrial inner membrane and is dependent on the mobilization of cholesterol from cellular stores. We report on the isolation of a human cDNA which encodes a mitochondrial protein called steroidogenic acute regulatory (StAR) protein, implicated in transport of cholesterol into mitochondria. Nucleotide and predicted amino acid sequence analyses indicate that the human and murine polypeptides are highly conserved, sharing 87% identity with an overall homology of 92%. Analysis of the distribution of StAR mRNA transcripts in human tissues by Northern blotting reveals several mRNA species, the most abundant of which is a 1.8 kb mRNA transcript present in testes, ovaries and kidneys. Using in vitro translated protein, we demonstrate that the StAR gene product can be efficiently imported into exogenously added mitochondria.

Hereditary sensory neuropathy: a case with pain and temperature dissociation.

A case of hereditary sensory neuropathy is described resembling Dyck's Type I hereditary sensory neuropathy. Sensory testing revealed marked pain impairment in feet and hands shading at mid calf to normal at mid thigh and shading above the wrist to normal at the elbow. Other sensory modalities including temperature were intact except painful heat and painful cold and they produced very little if any discomfort. Stimuli at 0 degrees C or 45 degrees to 70 degrees C elicited a temperature response but not pain. Sural nerve biopsy findings (including electromicroscopy) were consistent with a diagnosis of Type I hereditary sensory neuropathy, but also showed evidence of abortive axonal regeneration and profound Schwann cell vacuolation.