ESPE Abstracts

Background: There are few reports describing proximal deletions of chromosome 20p, making it difficult to predict the likely consequences of the deletion in this area. One report has described a proximal 20p11.2 deletion associated with panhypopituitarism, craniofacial dysmorphism, a small phallus with a semi bifid scrotum, and bilateral widely separated first and second toes. The only other report has demonstrated neurodevelopmental abnormalities associated with band 20p11.2 haploinsufficiency.

Objective(s): To report a child with dysmorphic features, GH deficiency and central hypothyroidism associated with a complex chromosomal rearrangement involving the short arm of chromosome 20.

Case report: The patient presented at the age of 4 years with short stature and was noted previously to have multiple dysmorphic features. Investigations confirmed GH deficiency and central hypothyroidism.

Methods/results: G-banding chromosome analysis of 12 cells from a peripheral blood sample revealed a male chromosome complement with a reciprocal translocation between the short arm of chromosome 6 and 20 (karyotype: 46 XY, t (6; 20)(p11.2; p11.2)). The patient carries a deletion of around 914-kb of the short arm of chromosome 20 within cytogenetic band 20p11. The parents had normal chromosomes. The deleted region harbors several candidate genes involved in regulating GH secretion.

Conclusion: Our patient carries a reciprocal translocation with a cytogenetic band 20p11.2, which is involved in the translocation and deletion of around 914-kb. The patient exhibited features related GH deficiency and hypothyroidism. Understanding the role of the deleted genes might provide further insights into the regulation of GH and thyroid hormone secretion. Therefore, our patient expands the spectrum of phenotypes associated with proximal deletions of chromosome 20.