NSDHL across dismech

NSDHL (NAD(P) dependent 3-beta-hydroxysteroid dehydrogenase NSDHL) is named by 1 disorder entry.

Normal function

ai-gene-review gives NSDHL's core molecular function as 3-beta-hydroxysteroid dehydrogenase [NAD(P)+]/C4-decarboxylase activity, acting in cholesterol biosynthetic process. This is the decarboxylating half of sterol C4-demethylation: after MSMO1 has oxidised a C4 methyl group to a carboxylate, NSDHL oxidises the 3-beta-hydroxyl and releases the carboxyl as CO2 in the endoplasmic reticulum membrane.

Causative record

CHILD Syndrome types NSDHL as causative, with the variant origin recorded as germline. The gene sits on the pathophysiology node NSDHL Loss of Function, which annotates the same C4-decarboxylase activity that ai-gene-review gives as the core function, marked as lost.

Where the layers disagree

ClinGen classifies NSDHL for 1 disease, and that disease has no dismech entry: CK syndrome. CK syndrome is the allelic disorder caused by hypomorphic NSDHL variants; CHILD Syndrome describes it only as a distinct allelic condition, so the ClinGen tier cannot be copied onto the CHILD record.

The NSDHL node in CHILD Syndrome carries a molecular function but no process term, so the KB and ai-gene-review share 0 GO process terms by exact identifier, even though both place NSDHL in cholesterol biosynthesis.