The analyses of human MCPH1 DNA repair machinery and genetic variations

Area of Science:

• Genetics and Molecular Biology
• Neuroscience
• Genomic Medicine

Background:

• Causal mutations in the Microcephaly/autosomal recessive primary microcephaly 1 (MCPH1) gene are linked to microcephaly and congenital hearing impairment.
• MCPH1 plays a crucial role in DNA repair, neurogenesis, and chromatin condensation, coordinating multiple repair mechanisms.

Purpose of the Study:

• To investigate the role of MCPH1 in DNA repair pathways.
• To identify and analyze rare genetic variations in MCPH1 using the gnomAD database.
• To explore the biological effects and potential disease associations of these rare MCPH1 variants.

Main Methods:

• Analysis of genetic variations within the MCPH1 gene using the gnomAD database.
• In silico prediction of variant pathogenicity.
• Review of existing clinical databases (e.g., ClinVar) for variant-phenotype associations.

Main Results:

• Identified pathogenic variants in MCPH1, including p.Gly753Arg (missense), p.Asn189LysfsTer15 and p.Cys624Ter (frameshift), which are associated with microcephaly and listed in ClinVar.
• Discovered novel ultra-rare variants (MAF ≤ 0.001), such as p.Val10SerfsTer5 (frameshift, loss-of-function) and p.Ser571Ter (stop gained), without current phenotype linkage.
• MCPH1's involvement in two major DNA repair pathways was confirmed.

Conclusions:

• Rare and predicted pathogenic variants in MCPH1 warrant further investigation for phenotypic discovery.
• These findings highlight MCPH1 as a candidate gene for screening in patients with unexplained microcephaly and congenital hearing impairment.
• Understanding rare MCPH1 variants can advance the diagnosis and management of associated neurodevelopmental and sensory disorders.