Clinical and molecular characterization of TCF12 variants in an Asian pediatric cohort with craniosynostosis.

Haploinsufficiency of TCF12 (a bHLH transcription factor), mostly through truncating variants of the C-terminal bHLH domain.

Trio exome sequencing in ten Asian children with cranial deformities identified ten distinct heterozygous TCF12 variants, all classified pathogenic or likely pathogenic by ACMG (six inherited, four de novo). Seven patients had imaging-confirmed craniosynostosis, mostly coronal. Most variants were truncating, spread across exons 14-19 and predicted loss of function; a bHLH-domain missense (p.Arg603Trp) impairs DNA binding. The cohort confirms haploinsufficiency as the central mechanism, with incomplete penetrance and mild or evolving phenotypes.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

The main contribution is documentation in an Asian population and a useful reminder of TCF12 incomplete penetrance — a carrier parent may be barely affected, which complicates counselling. Nothing groundbreaking mechanistically (haploinsufficiency already established), but welcome genotype-phenotype data for family surveillance.

Analysis by Dr Thibaut Benquey