P. J. L. Cook

Further data on the adenosine deaminase (ADA) polymorphism and a report of a new phenotype

In a study of human red cell adenosine deaminase (ADA) three different types of isozyme patterns were identified (Spencer, Hopkinson & Harris, 1968). One phenotype designated ADA 1 was found in about 89 % of the English population, the second phenotype, ADA 2-1, was found in about 11 yo of the population and the third phenotype, designated ADA 2, was seen only once in a survey of 580 unrelated English people. Sixty-seven families were studied and the family data suggested that the three ADA phenotypes were determined by two autosomal alleles ADA1 and ADA2; phenotypes ADA 1 and ADA 2 corresponding to the homozygous genotypes ADAlADAl and ADAaADA2 respectively and phenotype ADA 2-1 corresponding to the heterozygous combination ADA1ADA2. This paper contains further family data and more extensive population data on the ADA polymorphism and also a description of a new phenotype.

The genetics of α1-antitrypsin: a family study in England and Scotland

The results of Pi typing 5237 unrelated Caucasians are presented, together with the phenotypes of 2203 children from 1156 families. The estimate of the gene frequencies in the United Kingdom are Pi-M equal 0-9303, Pi-S equal 0-050, Pi-Z equal 0-0141, Pi-minus equal 0-0015, Pi-V equal 0-0004. Evidence for three new alleles, Pi-W2, Pi-Y2 is presented. The results of twin studies and quantitative studies are discussed.

Genetically determined electrophoretic variants of human red cell NADH diaphorase.

Human red cell NADH diaphorase isozyme patterns have been examined in blood samples from 2783 unrelated individuals by starch gel electrophoresis. Most people exhibit a single banded isozyme pattern, designated phenotype Dia 1. Twenty‐nine people with variant isozyme patterns were encountered. Five different phenotypes (Dia 2‐1, 3‐1, 4‐1, 5‐1 and 6‐1) were identified, which from family studies appear to represent heterozygous combinations of one or other of a series of rare alleles (Dia2, Dia3, Dia4, Dia5 and Dia6) with a common allele (Dia1) at an autosomal locus.

Assignment of the human locus determining phosphoglycolate phosphatase (PGP) to chromosome 16

The segregation of human phosphoglycolate phosphatase has been studied in 52 independent human-rodent hybrids and 69 subclones. The results suggest that human PGP is on chromosome 16. Family data suggest that PGP is not close to 16qh or alpha Hp. The most likely regional assignment for PGP would appear to be 16p13 or 16p12, but a site on 16q cannot be entirely excluded. New data on 16qh and alpha Hp suggest that the male recombination fraction between these loci is about 0.2.

Linkage between dentinogenesis imperfecta and Gc

A large family with dentinogenesis imperfecta shows that this locus is linked to the Gc locus on chromosome 4q. The maximum lod score is + 7.9 at a male recombination fraction of 0.05 and female recombination fraction of 0.24.

Pulmonary Emphysema and α1-Antitrypsin Deficiency

Of 72 patients with radiological evidence of pulmonary emphysema, emphysema occurred either alone or in association with bronchitis in 61, and 8 of these (13%) were found to have α1-antitrypsin deficiency. The main features of this condition are: exertional dyspnoea of relatively early onset (generally between 30 and 45 years of age), severely impaired FEV1 and TLCO, and radiological emphysema predominantly affecting the lower zones of the lungs. It is probable that any patient with all the above abnormalities has α1-antitrypsin deficiency. There is evidence to suggest that cigarette smoking may hasten the onset of this type of emphysema.

Studies on a family with three cytogenetic markers

Herdiw (in the Press). marriage and classified by ABO blood group. A m . Hum. Genet. 22, 166. histories collected in a Medical Genetics Unit. Am. J . Hum. Genet. 16, 1.

Exclusion mapping illustrated by the MNSs blood group

An exclusion mapping method is described which attempts to combine in a compact form negative information from deletion studies and studies on families segregating for existing reference markers, centromere markers and familial translocations. A meiotic map is provided for exclusion mapping. Chromosome 22 is used as a worked example of the exclusion mapping of the MNSs blood group. A particular assignment for MNSs to the q28 or q31 region of chromosome 4 is suggested by this method.

Segregation of ABO, AK1 and ACONs in families with abnormalities of chromosome 9.

Some families with abnormalities of chromosome 9 have been combined with others from the literature to show that AK1 and ABO must lie near the end of that chromosome. Current evidence suggests that both lie in band 9q34. MNSs, GPT and Gc can be excluded from chromosome 9.

Segregation of genetic markers in families with chromosome polymorphisms and structural rearrangements involving chromosome 1

In a previous paper we have presented data from family studies on the linkage relationships of PGM,, Rh, PGD, PEP-C and F y , loci thought to be on chromosome 1 (Robson et al. 1973). Recombination fractions between pairs of loci suggested that the most likely gene order is PGM, : Rh : PGD: PEP-C : F y , but only between PGM, and Rh and between Rh and PGD are the lod scores significant. I n this paper we shall present data on the same markers in families with translocations and variants of chromosome 1, in an attempt to fit the meiotic map to the cytological data.