Peter Bowen

Partial trisomy 12p due to t(12;21)pat translocation

SummaryPartial trisomy (interchromosomal duplication) of the short arm of chromosome No. 12 was observed in an infant girl with psychomotor retardation, prominent forehead, ptosis of the right eyelid, esotropia/exotropia, flat nose, hypotonia and other anomalies. A comparison of her features with those in five reported cases with a similar chromosomal imbalance shows certain features common to all, but the material is too limited for definitive characterization of a trisomy 12p syndrome.

Partial trisomy 4q due to familial 2/4 translocation

SummaryThe case of a 5-year-old boy with partial trisomy for the long arm of chromosome No. 4 is described. The pattern of abnormal development in this and in 12 previously reported cases is similar, but the phenotype is not as characteristic as that associated with some other types of chromosomal imbalance. The most consistent features are: growth and mental retardation, small head with narrow forehead, short philtrum, relatively large ears with incomplete differentiation of the pinnae, cryptorchidism, oedema of the hands and/or feet, and renal anomalies. Abnormal development of the thumb was present in 4 of 13 cases. Eleven of the 13 families had balanced translocation carriers whose future offspring would be at increased risk for a mental retardation syndrome.

Caudal regression anomalad (sacral agenesis) in siblings

Hypoplasia of the caudal end of the spine and associated anomalies were observed in two male siblings who also had congenital heart disease. The disorder has overlapping features with the VATER association and the caudal regression anomalad, and probably has a genetic basis, although the mode of inheritance is not clear.

Thymus deficiency in an infant with a chromosome t(18;22)(q12.2;p11.2)pat rearrangement

The finding of an unbalanced t(18;22)pat chromosome rearrangement in a boy with multiple anomalies including apparent absence of the thymus is described. The observation is of interest because of the reported association of chromosome 22 rearrangements with the DiGeorge sequence. In contrast to previous reports of this association, the deletion involving chromosome 22 is confined to the short arm.

Balanced t(8;9)(q12;q33)pat carrier with phenotypic abnormalities attributable to a de novo terminal deletion of the long arm of chromosome 7.

SummaryA girl observed from birth to age 16 months had multiple congenital anomalies including growth and developmental retardation, microcephaly (-4 SD), bulbous nose, prominent lips and philtrum, esotropia, latent hypermetropia, and spasticity. Chromosome analysis showed her to be a balanced carrier of a t(8;9)(q12;q33)pat translocation. In addition, she had a de novo deletion of a distal segment of the long arm of chromosome 7. Seven Previously reported cases with deletions involving 7q were reviewed and had a number of nonspecific features in common, with microcephaly of a comparable degree in one of these. Studies of the Kidd (Jk) blood groups and Hageman factor were done because of the tentative assignment of their respective loci to distal 7q. Location of the Kidd (Jk) locus on the deleted segment can be excluded on the basis of heterozygosity of the proposita for the a and b alleles. Hageman factor was not decreased, which suggests that this locus is also not on the deleted segment.

Serum Protein Polymorphisms in Indians of Western Canada

Serum protein types were determined for Canadian Indians belonging to three separate linguistic groups. The Hp 1 frequencies were within the range predicted on the basis o

Spontaneous abortion. Chromosome studies on 41 cases and an analysis of maternal age and duration of pregnancy in relation to karyotype.

Abstract The relatively frequent occurrence of chromosomal abnormalities in spontaneous abortuses offers an opportunity to gain additional insight into the mechanisms and consequences of alterations in the karyotype. Studies on 41 successfully cultured specimens showed abnormalities belonging to each of the three major classes previously reported (autosomal trisomy, X-monosomy, and triploidy) as well as one case of mosaicism and one with a structural abnormality. Analyses of pooled data showed a higher mean maternal age and shorter mean period of gestation for trisomic abortuses than for abortuses associated with X-monosomy, triploidy, and normal chromosomes. No influence of maternal age could be demonstrated for X-monosomic or triploid abortions when these were compared with abortions having normal chromosomes. An association of triploidy with missed abortion was noted and may be significant.

Familial paracentric inversions inv(2)(q31q35) and inv(8)(q22.3q24.13) ascertained through reproductive abnormalities

SummaryTwo cases of familial paracentric inversion, one in the long arm of chromosome 2 and the other in the long arm of chromosome 8, are described. The first was ascertained in a woman who was studied because of recurrent abortions. The second was ascertained in the father of a girl with the trichorhinophalangeal syndrome and an interstitial deletion in 8q. The latter is the first case in which unequal crossing over in an inversion loop can be inferred in a male carrier of a paracentric inversion. The reasons for the relatively low frequency of paracentric inversions observed and factors which affect the pregnancy outcome are discussed.

Trembling chin : a report of this inheritable dominant character in a four-generation Canadian family

Trembling chin is an unusual, benign, dominant trait. We describe the condition in a fourgeneration Canadian family. Investigations, which included E.E.G., electromyograph and facial nerve conductance studies on affected and unaffected individuals, were normal. Premature hearing loss, present in all affected members of this family over age 50, strongly suggests an association of trembling chin with otosclerosis. The merits of early diagnosis and preventive treatment for otosclerosis in persons affected by trembling chin are discussed.