Recurrent duplications of 17q12 associated with variable phenotypes.

Area of Science:

• Genetics
• Human Genetics
• Clinical Genetics

Background:

• Recurrent duplication of chromosome 17q12 (17q12 duplication) is rare.
• Phenotypic variability associated with 17q12 duplication complicates clinical identification.

Purpose of the Study:

• To further define the clinical features of individuals with 17q12 duplication.
• To expand the understanding of the phenotypic spectrum associated with this genomic alteration.

Main Methods:

• Multi-institutional collaborative effort collecting detailed clinical information.
• Analysis of 30 patients and 2 siblings with 17q12 duplication.
• Review of inheritance patterns and identification of additional copy number changes.

Main Results:

• Developmental delays (mild to severe) were common.
• Diverse dysmorphic features were observed, but no consistent recognizable pattern.
• Newly associated features include growth abnormalities, cataracts, microphthalmia, tracheomalacia, and others.
• Majority of duplications were inherited; some parents had learning disabilities or microcephaly.
• Additional copy number changes (e.g., 16p11.2 deletion) were identified in some patients.

Conclusions:

• The clinical spectrum of 17q12 duplication is broader than previously recognized.
• Genomic modifiers may contribute to the observed phenotypic variability.
• Further research is needed to fully understand the implications of 17q12 duplication.