Epimutation at human chromosome 14q32.2 in a boy with a upd(14)mat-like clinical phenotype

Area of Science:

• Genetics
• Epigenetics
• Human Molecular Genetics

Background:

• Maternal uniparental disomy of chromosome 14 [upd(14)mat] is a rare genetic condition.
• Previous reports linked deletions and epimutations in the 14q32.2 region to upd(14)mat-like phenotypes.

Observation:

• A patient presented with a phenotype consistent with upd(14)mat, including low birth weight, hypotonia, and developmental delay.
• Standard cytogenetic and molecular analyses, including SNRPN methylation, were normal.
• Methylation analysis at 14q32.2 revealed significant hypomethylation in key differentially methylated regions.

Findings:

• The patient's condition was not caused by full or segmental upd(14)mat or a microdeletion at 14q32.2.
• A novel epimutation in the 14q32.2 imprinted region was identified as the cause of the upd(14)mat-like phenotype.
• This case highlights the role of epimutations in imprinting disorders.

Implications:

• Epimutations at 14q32.2 can mimic the clinical features of upd(14)mat.
• Accurate molecular diagnostics require comprehensive analysis of imprinting regions, including methylation studies.
• Further research is needed to understand the spectrum and mechanisms of 14q32.2 epimutations.