dup1q211q23

dup1q211q23 refers to a chromosomal duplication involving a portion of the long arm of chromosome 1, from band 1q21.1 to 1q23. It represents a partial trisomy of that genomic interval and results in increased gene dosage for all genes contained within the duplicated region. The size of the duplication and the genes included can vary between individuals, contributing to a range of possible clinical outcomes.

Inheritance and mechanism. Duplications of 1q21.1–q23 can occur de novo or be inherited from a parent who carries a balanced rearrangement or an unbalanced copy number variation. They are usually detected by molecular cytogenetic methods that measure copy number across the genome. The clinical impact depends on the specific genes involved and the size of the duplicated segment.

Clinical features. The phenotype associated with dup1q211q23 is variable and highly dependent on the extent of the duplication. Reported features in some individuals include developmental delay or intellectual disability, delayed speech and language development, hypotonia, autism spectrum features, and congenital anomalies such as heart or other organ system abnormalities. However, many cases show a broad spectrum of presentation, with some individuals exhibiting mild or no noticeable deficits. Incomplete penetrance and variable expressivity are common.

Diagnosis and management. Diagnosis is typically achieved through array comparative genomic hybridization (array CGH) or SNP-based microarray, with confirmation by karyotyping or fluorescence in situ hybridization (FISH) as needed. Management is tailored to the individual and often involves a multidisciplinary team, including developmental, neurological, and cardiology assessments, along with early intervention services, education plans, and genetic counseling for families.

See also. Other 1q duplications and deletions (copy number variations) with variable clinical significance.