NCAPD2

Chr 12AR

non-SMC condensin I complex subunit D2

Also known as: CAP-D2, CNAP1, MCPH21, hCAP-D2

NCBI Gene: 9918 ENSG00000010292 UniProt: Q15021 OMIM: 615638

NCAPD2 encodes a regulatory subunit of the condensin complex that is essential for mitotic chromosome condensation and resolution of DNA catenanes between sister chromatids during cell division. Mutations cause primary autosomal recessive microcephaly 21, reflecting the protein's critical role in neurogenesis where accurate chromosome condensation in neural stem cells affects neuron pool size and cortical development. This gene is highly constrained against loss-of-function variants, indicating its essential cellular function.

OMIM ResearchSummary from RefSeq, UniProt

Enables histone binding activity. Involved in mitotic chromosome condensation and positive regulation of chromosome condensation. Located in several cellular components, including condensed chromosome; microtubule organizing center; and nuclear lumen. Part of condensin complex. Implicated in primary autosomal recessive microcephaly 21. [provided by Alliance of Genome Resources, Jul 2025]

OMIM ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

Microcephaly 21, primary, autosomal recessiveMIM #617983

Clinical highlights

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

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P/LP submissions

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P/LP missense

0.58

LOEUF

LOF

Mechanism· G2P