GLYCEROL KINASE-DEFICIENCY IN 2 BROTHERS WITH AND WITHOUT CLINICAL MANIFESTATIONS

We report two brothers with glycerol kinase deficiency (GKD). The olde r brother had serious clinical symptoms, mental and growth retardation , abnormal skeleton, spontaneous fractures and premature loss of abnor mal teeth. He and his mother had low serum phosphate levels. He had el evated serum and urine glycerol levels and GKD was found in cultured f ibroblasts. Prenatal diagnosis was performed in the second pregnancy, Glycerol kinase activity was considered normal in a chorionic villus s ample of the foetus. After birth, it was found that the boy had elevat ed serum and urine glycerol levels, Enzymatic analysis in cultured fib roblasts revealed that this boy also had GKD, in spite of having no ex pression of the disease. Chromosomal analyses in the parents and both boys were normal. Major rearrangements or deletions were not detected in molecular studies of DNA from the two brothers. The hybridisation p attern was normal and no allelic loss was observed.