Novel Unbalanced Translocation t(3;13)(q29;q34) in an Infant With Hydrocephalus.

Background: Copy number variations in chromosomal segments 3q29 and 13q34 are described in the literature, with varying reported phenotypic findings.

Case: We report the case of a male proband found to have prenatal hydrocephalus and intrauterine growth restriction at 32 weeks gestation. Genetic testing revealed a gain of a 4.8 megabase (Mb) region of 3q29 and a loss of a 5.4 Mb region of 13q33.3q34, yielding partial trisomy 3q29 and monosomy 13q34. FISH studies suggest that this unbalanced translocation resulted from a paternal balanced translocation. Findings at birth included respiratory distress requiring intubation, small birth weight, hypotonia, coagulopathy, pelvocaliectasis, and macrocephaly, with MRI demonstrating severe cortical thinning and white matter volume loss.

Conclusions: Though unbalanced translocations are highly individualized with varied phenotypes even among close relatives, this discussion of a proband and family members with translocation of chromosomes 3 and 13 contributes to published knowledge regarding these variants. We demonstrate the utility of online databases DECIPHER, OMIM, and Unique, as well as a translocation risk calculator, for understanding genetic anomalies and prognostic data for families affected by similar genetic variations.