A new heredity counseling service in Western Canada

ANIMAL GENETICS: Frederick B. Hutt. The Ronald Press Company, New York, 1964. 546 pp., $12.00.

INTERNATIONAL POPULATION CONFERENCE —CONCRAGES INTERNATIONAL DE LA POPULATION, OTTAWA, 1963: International Union for the Scientific Study of Population, Liège, 1964, 468 pp.

PROCEEDINGS OF THE 34TH SESSION, OTTAWA, 1963: Bulletin of the International Statistical Institute, Volume XL, Book 1, Toronto, 1964, pp. 319–494: Joint meetings with the International Union for the Scientific Study of Population.

THE CONCEPT OF RACE: Ashley Montagu, editor. Free Press of Glencoe, New York, 1964. 270 pp., $5.95.

PREGNANCY, CONCEPTION AND HEREDITY: Eric Weiser (Translated from the German by Therese Pol; So ensteht der Mensch: Von Zeugung und Vererbung, Ullstein Bücher, 1959). Blaisdell Publishing Co., New York, 1965. 148 pp., $1.50.     

Alternative models of counseling for genetic disorders

Abstract

A sample survey was conducted of a nationwide voluntary association whose purpose is to challenge societal pressures to have children and to provide support for those choosing to remain childless. The membership was predominantly under 35 years of age and married, almost entirely Caucasian, disproportionately concentrated in the higher education and income categories, and not committed to religion. Asked to rate the importance of various reasons for their decision not to have children, members under 35 years of age most frequently cited the deleterious effect of children on personal independence, the responsibility of rearing a child, and the interference of children with the marital relationship. Two out of three members under 35 intending to have no children reported pressures to have children, with the media, friends, and coworkers (but not parents) most often named as the leading sources.     

Medical ethics in genetic counseling

Genetic counselling gives the doctor a peculiar responsibility according to medical deontology and professional ethics rules. Originality and specificity of that kind of counselling requires intensive discussion of the geneticist's attitude in front of the diagnosis and specially prenatal diagnosis.     

Novel PTEN germline mutation in a family with mild phenotype: Difficulties in genetic counseling

PTEN gene (phosphatase and tensin homolog deleted on chromosome ten, MIM 601628) is a tumor suppressor gene implicated in PTEN hamartoma tumor syndromes (PHTS) including Cowden syndrome, Bannayan–Riley–Ruvalcaba syndrome and Proteus-like syndrome. PTEN mutations have been more recently reported in children with macrocephaly and autism spectrum disorders or mental retardation, without other symptoms of PHTS. Although tumor risk has not been evaluated in these patients and their relatives, the same surveillance as for Cowden syndrome is usually proposed. We report a family including patients carrying a novel PTEN mutation and presenting with a mild phenotype consisting of macrocephaly, hypotonia during the first year of life and mild learning disabilities, without autistic features. None of these patients exhibited PTHS-related symptoms such as tumors, lipomas, vascular malformations or pigmented macules of the glans penis. This report raises the question of extending the indications of PTEN mutation screening to familial macrocephaly with learning disabilities. Detection of a mutation in this family led to difficult questions about surveillance, genetic counseling and familial information since the mother declined tumor screening and disclosure of genetic risk information to at-risk relatives.     

The distribution of randomly recovered X-ray-induced sex-linked genetic effects in Drosophila melanogaster

Cytogenetic analysis of more than 1500 randomly recovered lethal X chromosomes derived from 2000 and 3000 r X-ray exposures of post-meiotic male germ cells has made possible a plot of the distribution in different regions of the X chromosome of: (1) gene mutations associated with cytologically normal chromosomes, (2) mutations associated with chromosomal rearrangement breakpoints, (3) deficiencies, and (4) rearrangement breakpoints whether or not they are associated with mutations. The distribution of point mutations, vital loci and rearrangement breakpoints in different regions of the X chromosome is not proportional to either the number of bands or the relative DNA content. Further, the density of vital loci (those capable of mutating to a lethal allele) is quite different in some regions as compared to others. For example, vital loci in the 3AB region, which has been thoroughly studied by Judd and others, are at least as numerous as bands; whereas, the 3CD region, equally long, has only two vital loci. Other regions densely populated with vital loci include 1B, 1F-2A, 10A, 11A, and 19EF; sparsely populated regions include 6EF and 10B-10E. It seems reasonable to conclude that the recovered X-ray-induced mutants available for analysis do not represent a random sample of those initially induced in the exposed male germ cells.