Inborn Errors of Biotin Metabolism

The document discussed two newly discovered inborn errors of biotin metabolism, highlighting their significant impact on human physiology. The neonatal-onset disease was caused by a defect in the enzyme holocarboxylase synthetase, while the later infantile-onset disease involved a defect in the enzyme biotinidase. Both disorders presented with notable clinical symptoms affecting the skin and hair. The neonatal disease was characterized by alopecia totalis and a bright red scaly total body eruption, whereas biotinidase deficiency resulted in patchy alopecia and skin lesions similar to acrodermatitis enteropathica. Both conditions were further complicated by recurrent, life-threatening episodes of acidosis and massive ketosis.