Gene and protein:ZNF462 (9q31.2) encodes a large, vertebrate-specific zinc finger protein of 23 C2H2 zinc finger domains that functions as a chromatin-associated transcriptional regulator and chromatin reader. The reference transcript is NM_021224.6 (isoform 1, the longest transcript); isoform 2 (NM_001347997.1) uses an alternative in-frame splice site in the 5' coding region. Note that some publications list the locus as 9p31.2; the correct cytogenetic band is 9q31.2 (confirmed by contiguous 9q31.2 deletion reports).
Mechanism of disease:WSKA results from haploinsufficiency (loss of function). The reported variant spectrum is predominantly truncating frameshift variants are most common, followed by nonsense variants (both predicted to trigger nonsense-mediated decay), together with whole-gene or contiguous 9q31.2 deletions and rare balanced translocations that disrupt ZNF462. The majority of pathogenic variants cluster in exon 3, which constitutes approximately 54% of the coding region. No genotype-phenotype correlation has been established, and molecular results cannot predict clinical severity.
Functional biology:work on the murine orthologue Zfp462 shows that the protein safeguards neural lineage specification by recruiting the H3K9-specific histone methyltransferase complex G9A/GLP to transposable-element-derived enhancers. This seeds H3K9me2 heterochromatin that restricts binding of pluripotency transcription factors (OCT4, SOX2) and silences meso-endodermal genes. Loss of Zfp462 causes ectopic activation of lineage-inappropriate genes and impaired neural differentiation, providing a plausible mechanistic basis for the neurodevelopmental phenotype. Zfp462 has additionally been implicated as a RUNX2 co-factor in osteoblast differentiation, consistent with its broad developmental role.
Diagnostic testing:sequence analysis of ZNF462detects the majority of pathogenic variants (approximately 17 of 21 probands in the largest series). Chromosomal microarray detects contiguous 9q31.2 deletions; karyotype identifies rare balanced rearrangements involving ZNF462. Where the phenotype is non-specific, exome or genome sequencing (or an intellectual-disability panel that includes ZNF462) is appropriate. Testing of both parents is recommended to confirm de novostatus; germline mosaicism has been documented and slightly increases the recurrence risk when the variant is not detectable in parental leukocyte DNA.
ZNF462