Genetic Analysis of 17q Terminal Partial Trisomy

Area of Science:

• Genetics
• Human Genetics
• Chromosomal Abnormalities

Background:

• Chromosomal trisomy syndromes present with varied phenotypes, including intellectual disability.
• Partial trisomy of the distal 17q (17qter trisomy) is a rare chromosomal anomaly.
• 17qter trisomy is characterized by psychomotor and growth deficits, facial dysmorphism, and microcephaly.

Purpose of the Study:

• To describe three patients from two unrelated families with terminal trisomy 17q.
• To analyze the genetic mechanisms leading to these chromosomal aberrations.
• To summarize existing literature on genotype-phenotype correlations for 17qter trisomy.

Main Methods:

• G-banding karyotype analysis.
• Chromosomal microarray analysis.
• Literature review for genotype-phenotype correlations.

Main Results:

• Family 1: A child with a 31.3 Mb mosaic duplication on chromosome 17.
• Family 2: Dizygotic twins with a 263 kb deletion on chromosome 15 and a 9.2 Mb duplication on chromosome 17.
• Normal karyotyping results in parents of Family 2, suggesting de novo events.

Conclusions:

• These cases provide novel insights into the diagnosis of terminal trisomy 17q.
• The findings contribute to understanding genotype-phenotype correlations in 17qter trisomy.
• This research can aid in the detection and genetic counseling of individuals with this rare condition.