Mental retardation in a child with a long B-group chromosome.

Abstract

A long unpaired B-group chromosome has been described in 12 reports (Edwards et al., 1962;Gagnon et al., 1963; Bray and Ann Josephine, 1964; Court Brown et al., 1964;Wallace and Anderson, 1964;Makino, Aya, and Sasaki, 1965;Mann et al., 1965;Gendel and Wasserman, 1966;Trujillo et al., 1966;Hsu et al., 1967;Shaw, Cohen, and Hildebrant, 1965;Atkins and Feingold, 1967). In all but one of these (Shaw et al., 1965) the excessive length is attributed to the addition of chromosomal material to the long arm, but there appears to be little phenotypic resemblance among them.Since it is possible that as more cases are reported distinct phenotypes will emerge, we would like to report another case of a child with a long B-group chromosome. Case ReportThe patient, a boy born May 18, 1962, is one of four children born to an unmarried mother. At the time of birth the mother was 27 years of age. No physical or mental abnormalities were evident in either parent and the other three children were reported to be developing normally.The pregnancy was unremarkable except that the mother had influenza in the last month of gestation. The labour lasted 48 hours, but delivery was spontaneous. The birthweight was 2380 g. (5 lb. 4 oz.). There were some breathing difficulties immediately after delivery, and he was kept in an incubator for about two weeks. Twitching was reported in the neonatal period.

Developmental abnormalities in a patient with karyotype 46,XX,bq+.

“…There are also five reports of the spontaneous appearance of Bq + chromosomes (Atkins and Feingold, 1967;Bray and Ann Josephine, 1964;Gagnon et al, 1963;Gendel and Wasserman, 1966;Trujillo et al, 1966) and two additional cases in which full family studies were not possible (Iivanainen and Gripenberg, 1967;Tischler, Corey, and Co-Te, 1968). Wallace and Anderson (1964) reported a female with 45 chromosomes, who had a large Bq + chromosome, possibly derived from a t(Bq + ;Dq -), she showed features of Patau's syndrome.…”