Treatable Intellectual Disability

Holocarboxylase Synthetase Deficiency

BIOCHEMICAL DEFECT

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DIAGNOSIS

Gene
HLCS (AR)

Diagnostic Test
Urine Organic Acids

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SIGNS & SYMPTOMS

Neurological
Encephalopathic crisis, epilepsy, subependymal/parenchymal cysts (MRIscan)

Non-Neurological
Rash, alopecia

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THERAPY

Treatment
Biotin Supplement

Level of Evidence
4

Clinical Practice
Standard of Care

Treatment Effect
Improves psychomotor development/IQ, neurological & systemic manifestations



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Holocarboxylase Synthetase (HCS) Deficiency

is a life-threatening early-onset form of multiple carboxylase deficiency (see this term), an inborn error of biotin metabolism, that, if untreated, is characterized by vomiting, tachypnea, irritability, lethargy, exfoliative dermatitis, and seizures that can worsen to coma. The exact prevalence of HCSD is unknown, but the condition is one of the rarest inborn errors of metabolism. (Source: Orphanet)

No information available from this source.

This disease is not (yet) listed on their website.