3-Hydroxy-3-methylglutaryl-coenzyme A lyase deficiency: biochemical studies and family investigation of four generations.

3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) lyase activity was determined by the recently described spectrophotometric method of Wanders et al. (1988a) in polymorphonuclear leukocytes and lymphocytes obtained from 33 members of a highly consanguineous Arab-Bedouin family belonging to four generations. Seven subjects were obligatory heterozygotes (parents and grandparents of three propositi); in seven additional subjects enzyme activity in both cell types was in the heterozygote range. No asymptomatic homozygotes were found. The results support the proposed autosomal recessive mode of inheritance of this disorder.