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Updated: Nov 25, 2025
FISH for Pre-implantation Genetic Diagnosis
Published on: February 23, 2011
Partial 5p Gain and 15q Loss in Three Patients from a Family with a t(5;15)(p13.3;q26.3) Translocation
Fernanda T Bellucco1, Bianca P Favilla1, Eduardo Perrone1
1Genetics Division, Department of Morphology and Genetics, Universidade Federal de São Paulo, São Paulo, Brazil.
Abstract:
Several patients with 5p duplication or 15q deletion have been reported in the literature, involving different chromosome regions and clinical features. Here, we describe a family in which we identified a 30-Mb 5p15.33p13.3 gain and a 2.5-Mb 15q26.3 loss in 3 individuals, due to a balanced familial translocation between chromosomes 5p and 15q. They presented a similar combination of clinical findings related to their genetic imbalances, but there were also phenotypic differences between them. Our analyses show that their clinical picture is mostly caused by the loss in 15q and not the gain in 5p, despite its much larger size. Our findings suggest that other genes, besides the IGF1R gene, in the 15q26.3 region, such as the CHSY1 gene, may have a great impact on the clinical picture of the syndrome. Our data emphasize the importance of detailed cytogenomic and clinical analyses for an accurate diagnosis, prognosis, and genetic counseling, providing an opportunity to improve genotype-phenotype correlations of patients with partial 5p duplication and 15q deletion syndromes.
Insights
A family with a balanced translocation between chromosomes 5p and 15q showed similar clinical features due to a 15q deletion. This highlights the critical role of specific 15q genes in the syndrome, not just the larger 5p duplication.
Area of Science:
- Genetics
- Molecular Biology
- Clinical Medicine
Background:
- Partial 5p duplication and 15q deletion syndromes are rare genetic disorders.
- Previous reports describe varied chromosomal regions and clinical manifestations.
- Familial translocations can lead to complex chromosomal imbalances.
Observation:
- A family presented with a balanced translocation between chromosomes 5p and 15q.
- Three individuals inherited a 30-Mb 5p15.33p13.3 gain and a 2.5-Mb 15q26.3 loss.
- Similar yet distinct clinical findings were observed among affected family members.
Findings:
- The clinical presentation was primarily attributed to the 15q26.3 deletion, despite the larger size of the 5p gain.
- Genes within the 15q26.3 region, such as CHSY1, may significantly influence the phenotype.
- The IGF1R gene in the deleted region was also considered but CHSY1's impact is highlighted.
Implications:
- Detailed cytogenomic analysis is crucial for accurate diagnosis and prognosis.
- Understanding genotype-phenotype correlations in 5p duplication and 15q deletion syndromes can be improved.
- This study provides valuable insights for genetic counseling in affected families.
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