Duplication of 5q21 in a mildly retarded male and his non-retarded mother

Euchromatic autosomal additions to chromosomal complements are typically associated with global effects including mental retardation (MR) and dysmorphism. We report a familial duplication that does not appear to cause consistent, significant effects. A hyperactive male with mild MR was referred for fra(X) testing at 8 yrs. His karyotype was fra(X) negative and normal except for an addition in one 5q. The abnormal 5 was also in the maternal karyotype, but all other parental chromosomes were normal. The addition (=8.5% the length of a 5) was interpreted as a duplication of band 5q21. FISH with Coatasome 5 (Oncor) showed the addition was from 5. The proband`s karyotype was designated 46,XY,dup(5)(q15q22.1)mat; his mother`s, 46,XX,dup(5)(q15q22.1). Single copy probes are being used to test the cytogenetic interpretation. At 39 yrs, the non-retarded, somewhat inattentive mother, who has a high school diploma and subsequent secretarial courses, cares for the proband and his chromosomally normal, but learning disabled sister at home. The family situation is chaotic with reported paternal psychiatric illness and abuse of the proband and his sister. The mother`s father is dead, but her four younger siblings and mother are reportedly normal. Their chromosomes have not been available. The proband was born at 40more » weeks following an uneventful pregnancy, with length and weight at the 5-10th centiles. He walked and talked at about one year. At 9 yrs, his ht/wt ratio was 10th centile. Foot length as <3rd centile; soft masses were present on the anterior ankles. He was otherwise physically normal. His estimated I.Q. was 75 and he was severely hyperactive despite Ritalin. This is the first report of a familial duplication in 5q; no identical, isolated case is known. Although additional family members need evaluation, the presence of the dup(5q) in the non-retarded mother suggests that it may not be associated with the proband`s MR.« less