Hypoplastic left heart in a female infant with partial trisomy 4q due to de novo 4;21 translocation

We present a female infant with mild dysmorphic features and congenital heart defect: hypoplastic left heart with aortic atresia and hypoplastic aortic arch, ventricular septal defect, and a nonrestrictive atrial communication. Chromosome analysis showed an unbalanced translocation that contained additional material from 4q translocated onto 21q. This resulted in partial trisomy 4 and monosomy for the 21q telomeric region. The derivative chromosome was characterized using G-banding, M-FISH, and whole chromosome painting. The karyotype was described as 46,XX,der(21)t(4;21)(q25;q22.3).ish(wcp4+;w-cp21+). Additional analyses with FISH probes specific for 21q 22.3, 21q22.2, 21q21.1, and 21q11.2 did not indicate any chromosome 21 duplication within the derivative chromosome 21. Monosomy for the telomeric portion of 21q was demonstrated using a tel 21q probe (Oncor). The patient underwent stage 1 Norwood procedure to manage her heart defect. Poor feeding and failure to thrive complicated the postsurgical period. The child subsequently underwent funduplication and feeding tube placement, and at 4.5 months of age presented with microcephaly and developmental delay. Hypoplastic left heart was previously reported with increased frequency in relatively common numeric chromosomal aberrations, such as monosomy X, trisomies 21, 18, and 13, and in various structural chromosomal defects. Our report presents new evidence for the co-occurrence of hypoplastic left heart with a duplicated portion of chromosome 4 distal to 4q25. In addition, monosomy for the telomeric region of chromosome 21 may have implications in the phenotype.