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A novel mosaic 1q32.1 microduplication identified through Chromosome Microarray Analysis: narrowing the smallest
Gianmaria Miolo1, Maria Grazia Giuffrida2, Giuseppe Corona3
1Medical Laboratory Department, Genetics Section, Pordenone Hospital, Italy; Medical and Preventive Oncology, IRCCS Aviano, National Cancer Institute, Italy.
Abstract:
Microduplications involving 1q32.1 chromosomal region have been rarely reported in literature. Patients with these microduplications suffer from intellectual disability, developmental delay and a number of dysmorphic features, although no clear karyotype/phenotype correlation has yet been determined. In this case report we describe two monochorionic-diamniotic twins with intellectual disability, abnormality of coordination and dysmorphic features associated with a de novo 280 kb mosaic microduplication of 1q32.1 chromosomal region, identified using a Chromosome Microarray Analysis (CMA) and confirmed by quantitative PCR analysis. The duplicated region encompassed entirely three OMIM genes KDM5B (*605393), KLHL12 (*614522), RABIF (*603417) and involved partially SYT2 (*600104). This unique case report allows to redefine the critical 1q32.1 microduplicated region implicated in the ethiopathogenesis of intellectual disability and developmental delay. Furthermore, it suggests that KDM5B gene can have a pivotal role in the development of neurodevelopmental disorders through its demethylase activity.
Insights
Rare microduplications in the 1q32.1 region are linked to intellectual disability and developmental delays. This study identifies a specific microduplication in twins, potentially pinpointing a critical region and the role of the KDM5B gene.
Area of Science:
- Genetics
- Neurodevelopmental Disorders
- Human Molecular Genetics
Background:
- Microduplications of the 1q32.1 chromosomal region are infrequently documented.
- Existing cases present with intellectual disability, developmental delay, and dysmorphic features, but a precise karyotype-phenotype correlation remains elusive.
Observation:
- This report details two monochorionic-diamniotic twins exhibiting intellectual disability, coordination abnormalities, and dysmorphic features.
- A de novo 280 kb mosaic microduplication of the 1q32.1 region was identified using Chromosome Microarray Analysis (CMA) and confirmed via quantitative PCR.
Findings:
- The duplicated region fully included OMIM genes KDM5B, KLHL12, and RABIF, and partially involved SYT2.
- This finding aids in redefining the critical 1q32.1 microduplicated region associated with intellectual disability and developmental delay.
Implications:
- The study suggests KDM5B may play a crucial role in neurodevelopmental disorders due to its demethylase activity.
- This case refines our understanding of the genetic underpinnings of intellectual disability and developmental delay linked to 1q32.1 microduplications.
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