Molecular cytogenetic characterization of partial trisomy of the long arm of chromosome 11 in a patient with multiple congenital anomalies.

Background: Partial trisomy of the long arm of chromosome 11 is a rare cytogenetic abnormality. It has been characterized by variable sized duplications that lead to a range of phenotypes including growth retardation, developmental delay/intellectual disability, and distinctive craniofacial abnormalities. Congenital heart defects, skeletal abnormalities, urogenital anomalies, and hypotonia are found in some affected individuals.

Methods: We describe a 16-year-old patient presented with most of the hallmark phenotypes of trisomy 11q syndrome as well as exhibiting symptoms of hearing loss, seizures, and abnormal endocrinological and ophthalmological findings. Routine chromosome analysis and subsequent chromosomal microarray analysis (CMA) were performed to detect genetic abnormalities in this patient.

Results: We identified an abnormal male karyotype with a derivative chromosome 4 due to an unbalanced translocation between chromosomes 4 and chromosome 11. The CMA results revealed a 56 Mb duplication of chromosome 11q14.1-qter and a 874 Kb terminal deletion of the short arm of chromosome 4.

Conclusion: A genomic imbalance resulting in partial trisomy 11q was found in a patient with multiple congenital anomalies. We compared the phenotypes of all known "pure" trisomy 11q cases in the literature and find that trisomy 11q23-qter is both recurrent and the most common cytogenetic abnormality found in the reported cases. It is associated with the core features of trisomy 11q syndrome.