[Unbalanced subtelomic rearrangement involving 9q and 22q in a child with mental retardation and multiple congenital anomalies].

OBJECTIVE

To determine genetic cause for a patient with development delay and multiple congenital anomalies.

METHODS

Routine karyotype analysis was performed for the patient and his parents. Array comparative genomic hybridization (array CGH) was performed for the patient to detect cryptic chromosome aberration.

RESULTS

Karyotype analysis revealed no obvious anomaly for the patient and his parents. Array CGH has detected a 2.8 Mb heterozygous deletion at 9q34.3 and an 8.1 Mb heterozygous duplication at 22q. Fluorescence in situ hybridization analysis of the patient revealed an unbalanced subtelomeric translocation 46, XY, der(9) t(9; 22) (q34.3; q13.2q13.33) mat, which has resulted in partial trisomy 22q and partial monosomy 9q. Clinical features of the patient included developmental delay, facial dysmorphism and multiple congenital anomalies. Upon subsequent pregnancy, FISH analysis revealed that the fetus has inherited the normal chromosomes 9 and 22 from his mother. Postnatal follow-up confirmed normal development milestone and physiques in the child.

CONCLUSION

An unbalanced translocation involving 9q and 22q has been found in a child featuring multiple congenital anomalies, which is due to a balanced translocation 9; 22 in his mother. Array CGH and FISH have also helped with discovery of subtelomeric rearrangement. Prenatal diagnosis of this aberration in subsequent pregnancies with FISH can prevent the recurrence of this disease.