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