Different X-linked KDM5C mutations in affected male siblings: is maternal reversion error involved?

Area of Science:

• Genetics
• Human Molecular Genetics
• Developmental Biology

Background:

• Genetic reversion is a natural process that can correct gene mutations, but its accuracy is not fully understood.
• Intellectual disability can arise from various genetic factors, including mutations in specific genes.

Purpose of the Study:

• To investigate the accuracy of genetic reversion as a mutation repair mechanism.
• To explore the potential role of reversion errors in generating somatic mutations and causing human diseases.

Main Methods:

• Whole-exome sequencing was used to identify mutations in the KDM5C gene in a family with intellectual disability.
• Analysis of mutation patterns in affected siblings and their mother to infer the timing and mechanism of mutation occurrence.

Main Results:

• Two distinct mutations (c.633delG and c.631delC) in the KDM5C gene were identified in affected siblings.
• The mother carried a de novo germline mutation (c.631delC) and a low-prevalence somatic mutation (c.633delG) on the same haplotype.
• The co-occurrence of these mutations on the same haplotype suggests an early embryonic reversion error in the mother.

Conclusions:

• This study provides evidence that genetic reversion can be an error-prone process.
• Reversion errors represent a novel mechanism for generating somatic mutations in human diseases.
• The findings highlight the complex genetic landscape underlying intellectual disability and other genetic disorders.