Amniocentesis was performed in a woman who previously had given birth to a boy who died at 12 months of age with a diagnosis of glyceroluria and adrenal insufficiency. A high amount of glycerol (9.0 standard deviations above mean for controls) was found in the amniotic fluid. Enzyme activity of glycerol-kinase (ATP:glycerol-3-phosphotransferase, EC 2.7.1.30) in the cultured amniotic fluid cells was very low. The pregnancy was terminated and a male fetus was aborted. Examinations of DNA isolated from the fetus did demonstrate deletions of two out of 16 DNA probes mapping to the short arm of the X-chromosome. The probes failing to hybridize to DNA from the fetus were C7 (DXS28) and L1.4 (DXS68), both mapping to Xp21.3 and located terminal to the Duchenne locus.