Complex glycerol kinase deficiency: an unusual cause of salt-wasting in males

We report the case of a male infant who at 10 days of life presented with salt-wasting. Congenital adrenal hyperplasia was excluded on the basis of normal 17 alpha-hydroxy-progesterone plasma levels evaluated before the onset of steroid replacement therapy. The incidental finding of hypertriglyceridaemia led us to suspect the condition of complex glycerol kinase deficiency which was confirmed by the direct measurement of serum glycerol (7.16 mmol/l, normal range 0.02-0.21). Serum creatine kinase was markedly elevated (5963 U/l, normal range 37-290). High resolution cytogenetic investigation of peripheral blood showed a small interstitial deletion within Xp21. The same deletion was found in the patient's mother although not in his maternal grandmother. We present this case in order to emphasize the necessity of evaluating plasma triglycerides in all neonatal males with salt-wasting which can not be explained by congenital adrenal hyperplasia. Plasma triglycerides measurement carried out using a routine clinical method which measures glycerol released after lipolysis facilitates early recognition of this syndrome, and enables appropriate therapy and subsequent genetic counselling.