Figure 2.

Pedigrees of families in which siblings of the proband were tested. Shaded = mental retardation. Black dot = aberration carrier.

A. Pedigree patient 2. The mother carried the same BP4-BP5 15q13.3 deletion as identified in the proband, who attends a regular primary school, with learning problems. The brother also had learning problems at primary school, however normal chromosomes.

B. Pedigree patient 3. Both sisters (II-I and II-IV) carried the same BP4-BP5 15q13.3 deletion as identified in the mild mentally retarded proband and her healthy father. The deletion was not found in the healthy mother and brother (II-III). Both sisters had had learning problems for which they attended a period of special schooling, however both had continued regular schooling.

C. Pedigree patient 4. Except for female II-III, all sibs carried the same BP4-BP5 15q13.3 deletion as identified in the mentally retarded proband and his healthy mother. Female II-I and male II-V both had had learning problems in childhood but both showed normal adaptive skills in adulthood. The remaining siblings (II-II, II-III and II-VI) never had had learning problems and finished normal primary and secondary school.

D. Pedigree patient 12. Both brothers had a mild developmental delay and both carried the BP4-BP5 15q13.3 deletion. The mother was not formally assessed but she appeared to have a borderline level of intelligence.

E. Pedigree patient 18. Father and daughter both have a BP3-BP4 deletion. The same deletion was also identified in her oldest brother and paternal uncle who both had had normal development. Her mentally retarded brother was also tested, but did not have the deletion.