Holocarboxylase Synthetase Deficiency

**Definition:** 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).

**Tree numbers:** - C16.320.565.100.620.380 - C16.320.565.202.720.380 - C18.452.648.100.620.380 - C18.452.648.202.720.380

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