High resolution replication banding combined with in situ hybridization for the delineation of a subtle chromosome rearrangement.

Molecular cytogenetic techniques were used to delineate a subtle chromosome rearrangement in an infant with growth and psychomotor retardation, abnormal scalp hair pattern, narrow palpebral fissures, broad nasal bridge, bulbous nose, small nostrils, thin lips in a cupid's bow configuration, bilateral simian creases, and unilateral cryptorchidism. Analysis using GTG-banded chromosomes at about 400 band level showed no obvious abnormality. Prometaphase analysis at about 600 band level showed an extra band at 14q32 on GTG-banding. The father had the same extra band suggesting a reciprocal translocation but the second chromosome involved in the translocation could not be identified. High resolution replication banding on the father's lymphocytes showed a balanced reciprocal translocation 46,XY,rcp(8;14)(q24.1;q32.1). The translocation was confirmed by in situ hybridization with an immunoglobulin heavy chain probe which maps to 14q32.3. The infant therefore had duplication of 8q24.1----qter and deficiency of 14q32.1----qter. His phenotype resembled that of patients with partial duplications of the distal long arm of chromosome 8.