Genetic-metabolic considerations in the sick neonate

Clinical approach to inherited metabolic diseases in the neonatal period: a 20-year survey

Every newborn with unexplained neurological deterioration, ketosis, metabolic acidosis or hypoglycaemia should be suspected of having an inherited error of intermediary metabolism. Many of these conditions can be diagnosed clinically with the aid of simple laboratory investigations. Since a substantial number of these diseases respond well to treatment but may otherwise be fatal, and in order to assure adequate prenatal diagnosis in subsequent pregnancies, a high index of suspicion and rapid diagnosis are necessary in the face of the clinical presentations described. According to three major clinical presentations observed in 218 neonates with inborn errors of intermediary metabolism (neurological distress 'intoxication' type, neurological distress 'energy-deficiency' type and hypoglycaemia with liver dysfunction) and according to the proper use of few laboratory investigations, we propose a method of diagnosis which groups these children into five categories. Initial therapy, and sophisticated investigations can be planned on the basis of this grouping.

Fructose-1,6-diphosphatase deficiency: glycerol excretion during fasting test

A Turkish boy had suffered since the age of 10 months from recurrent attacks of severe metabolic acidosis and hypoglycaemia precipitated by moderate respiratory tract infections. A liver biopsy showed lack of fructose 1,6-diphosphatase and absence of phosphorylase. The patient died in shock following fructose ingestion. Upon fasting, acidosis with increased lactate and glycerol excretion was found. Findings indicate that, in this inherited disorder of gluconeogenesis, lactic acidosis combined with increased glycerol excretion upon fasting are of diagnostic importance.