The neonatal form of MULTIPLE CARBOXYLASE DEFICIENCY that is caused by a defect or deficiency in holocarboxylase synthetase. HLCS is the enzyme that covalently links biotin to the biotin dependent carboxylases (propionyl-CoA-carboxylase, pyruvate carboxylase, and beta-methylcrotonyl-CoA carboxylase).

Synonyms: Early Onset Biotin Responsive Multiple Carboxylase Deficiency, HLCS Deficiency, Deficiencies, Holocarboxylase Synthetase, Carboxylase Deficiency, Multiple, Neonatal Form, Multiple Carboxylase Deficiency, Early Onset, Deficiency, Multiple Carboxylase, Neonatal Form, Deficiency, Holocarboxylase Synthetase, HLCS Deficiencies, Early-Onset Combined Carboxylase Deficiency, Early Onset Combined Carboxylase Deficiency, Holocarboxylase Synthetase Deficiency, Early-Onset Biotin-Responsive Multiple Carboxylase Deficiency, Deficiencies, HLCS, Deficiency, HLCS, Holocarboxylase Synthetase Deficiencies, Infantile Multiple Carboxylase Deficiency, Multiple Carboxylase Deficiency, Neonatal Form