Schizophrenia in an adult with 6p25 deletion syndrome

Abstract

Chromosomal deletions at 6p25-p24 are rare findings in patients with developmental delay. There is limited information about the adult phenotype. We present a 36-year-old patient with schizophrenia, mild mental retardation, progressive hearing deficits, and characteristic facial features. Ocular (Axenfeld-Rieger anomaly) abnormalities were diagnosed in infancy; vision, however, has remained unimpaired. There were no other major congenital anomalies. Brain imaging showed only minor changes. There was no family history of intellectual deficits or psychosis. Karyotyping revealed a 6p25 deletion, and detailed fluorescence in situ hybridization (FISH) analyses using 23 probes confirmed a 6.7 Mb 6p25-pter deletion. The breakpoint is near a possible 6p25-p24 locus for schizophrenia. Psychotic illness may be part of the neurodevelopmental abnormalities and long-term outcome of patients with 6p terminal deletions. Other similarly affected patients likely remain to be diagnosed in adult populations of schizophrenia and/or mental retardation.

Fig. 1

Frontal and profile views of patient at age 36 years showing characteristic facial features of 6p25 deletion syndrome.

Fig. 2

Example of a result of in situ hybridization on metaphase chromosomes of the case. Probes were labeled with biotin and digoxigenin and detected using fluorescein isothiocyanate or tetramethylrhodamine isothiocyanate systems, respectively. Chromosomes were counterstained with 4′,6-diamidino-2-phenylindole. Probe DJ 86O19 (green) hybridized on chromosomes 6 and del(6) whereas the more distal probe B24 (red) hybridized only to the normal chromosome (see Table I).