[Contiguous gene deletion syndrome in Xp21: the association between glycerol kinase deficiency, congenital suprarenal hypoplasia and Duchenne's muscular dystrophy].

Introduction: Complex glycerol kinase (GK) deficiency is a contiguous deletion of genes in Xp21 with loss of the locus for GK, for congenital adrenal hypoplasia (AHC) and/or for Duchenne's muscular dystrophy (DMD). We report the case of a 7-year-old patient with this rare disease.

Case Report: Our patient was a full-term male, with normal gestation and delivery, and no relevant family history. At the age of 11 days he presented a clinical picture of salt loss with lethargy, vomiting, metabolic acidosis, hypoglycaemia, hyponatraemia and hyperpotassaemia. Fluid therapy and treatment with corticoids was established. The patient's condition developed with moderate mental retardation and progressive muscular weakness. In the physical examination, the skull and face were seen to be 'hourglass' shaped. Decompensations associated to infectious processes and fasting hypoglycaemia, hydroelectrolytic disorders and ketoacidosis are all frequent. Lab findings showed a drop in cortisol levels, elevation of muscle enzymes, 'pseudohypertriglyceridaemia' and raised levels of glycerol in plasma and urine. Karyotype and neuroimaging tests were normal. A myopathic pattern was observed in the electromyogram. The genetic study confirmed the deletion in Xp21 of the genes responsible for DMD, the GK deficit and AHC.

Conclusions: Early identification of this disease makes it possible to foresee the acute metabolic decompensations and to establish suitable genetic counselling. CK and triglyceride counts should be performed in all male patients that present a suprarenal hypoplasia; if levels are high, then it is necessary to confirm the raised glycerol values and to carry out a confirmatory genetic study.