Pulmonary hypertension associated with nonketotic hyperglycinaemia

Nonketotic hyperglycinaemia (NKH) is an autosomal recessive disorder charac terized by defective glycine degradation by the mitochondrial glycine cleav age system. The clinical features include lethargy, hypotonia, apnoea, seiz ures and severe psychomotor retardation, all attributed to the accumulation of glycine in the nervous system. Pulmonary hypertension (PHN) has not bee n reported in NKH. We describe four patients with NKH who had PHN in additi on to the characteristic manifestations of NKH. This newly recognized assoc iation might provide additional insight into the underlying pathophysiology of PHN.