MG-130 Pure duplication of 1q42.11-q44(QTER): Further clinical delineation of a rare terminal duplication syndrome

Abstract

Background Pure partial trisomy of 1q42 to 1q44 (terminal end) is an extremely rare chromosomal abnormality reported in only 5 patients to date. We present one additional case with the breakpoints molecularly characterised by array CGH. Clinical features are similar to those previously described with 1q42 terminal duplication syndrome. Objective To contribute to the growing clinical knowledge of pure 1q42 terminal duplications. Design/method A G-banded karyotype with subsequent FISH to confirm the location of the breakpoints was performed. The breakpoints were further refined with an array Comparative Genomic Hybridization (CGH) using the oligoarray platform CytoChipTM ISCA 8 × 60K v2.0. Results Our case has a pure partial duplication of chromosome 1q42.11 to the terminal end, resulting from a one-way translocation of this segment to the distal long arm of chromosome 2. Array CGH identified this to be 24.8 Mb in size (nucleotides 222,299,920 – 247,179,262; NCBI36/hg 18). Array CGH did not identify a deletion on chromosome 2. Conclusions We describe a 12-year-old male with the distinctive appearance similar to those previously described with 1q42 duplication syndrome including macrocephaly, down-slanting palpebral fissures, a high arched palate, low-set, abnormal ears and cryptorchidism. Height measured 138.5 cm (just below the 3rd percentile) and weight measured 34.9 kg (3rd–10th percentile), while head circumference measured 53.8 cm (50th percentile). Additional features not previously reported include two conjoined teeth, mild pectus carinatum and microphallus. He has a history of developmental delay and intellectual disability, aggressive and self-injurious behaviour and obstructive sleep apnea.