Copy number variants and rasopathies: germline KRAS duplication in a patient with syndrome including pigmentation...

Area of Science:

• Genetics
• Molecular Biology
• Human Physiology

Background:

• Rasopathies are rare genetic syndromes caused by germline mutations in the RAS/MAPK pathway, typically point mutations affecting signaling.
• While duplications in RAS/MAPK pathway genes are rare, this study investigates a familial case with a 12p duplication involving the KRAS gene.

Discussion:

• The patient presented with a phenotype overlapping Rasopathies, including developmental delay, short stature, dysmorphic features, and distinct pigmentation abnormalities.
• Genetic analysis revealed a ~10.5 Mb duplication at 12p encompassing the KRAS gene in the patient and their mother, who also exhibited developmental delay and café-au-lait spots.
• This suggests that KRAS gene duplication may contribute to the Rasopathy phenotype, particularly the characteristic pigmentation anomalies.

Key Insights:

• Identified a novel ~10.5 Mb duplication at 12p including the KRAS gene in a familial case with Rasopathy-like features.
• Demonstrated that KRAS gene duplication can be a cause of Rasopathies, expanding the known genetic basis of these disorders.
• Highlighted the clinical overlap between KRAS duplication and other Rasopathies, emphasizing the need for comprehensive genetic evaluation.

Outlook:

• Recommends array comparative genomic hybridization (array-CGH) or other gene/exon copy number variation (CNV) assessments for RAS/MAPK pathway genes in individuals with unexplained Rasopathy phenotypes.
• Suggests further research into the specific mechanisms by which KRAS gene duplications lead to Rasopathy phenotypes.
• Advocates for including KRAS copy number analysis in the diagnostic workup for suspected Rasopathies.