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T Jenkins

Publications and source records attributed to T Jenkins.

At least 181 records · Page 10Linked to original sources
PubMed1985

A genetic profile of the South African Ashkenazi Jewish population.

The South African Ashkenazi Jewish population is described in terms of the prevailing frequencies of the genes at 25 red cell enzyme and serum protein loci and 4 placental enzyme loci. Variation was encountered in 23 of these systems. The Tay-Sachs allele which occurs at polymorphic frequencies in Ashkenazi populations was found at a frequency of 0.022, which suggests that approximately 1 baby with Tay-Sachs disease could be expected out of every 2,000 born in this community should preventive measures not be taken. The atypical serum pseudocholinesterase cholinesterase allele was encountered at a relatively low frequency and instances of scoline apnoea would be expected to occur only during approximately 1 out of every 10,000 surgical operations performed. A single case of glucose-6-phosphate dehydrogenase deficiency was discovered during the survey. In general, the allele frequencies in the systems studied do not differ radically from those of Ashkenazi populations living in other parts of the world. In accordance with other Ashkenazi populations, the frequencies of certain alleles in our samples provide support for the belief that the Ashkenazim have their origin in the Middle East.

Alleles↗
PubMed1985

Segregation patterns and phenotypes of unbalanced offspring in a large family with (10;18) chromosome translocation.

We describe a large family in whom a balanced 10;18 chromosome translocation is segregating through five generations. Six severely mentally retarded relatives and an abnormal fetus further define the phenotypic expression of dup (18q21----qter). Other segregants detected prenatally included a fetus with deletion 18q21----qter and two fetuses with dup(18pter----q21) owing to tertiary trisomy. One of the latter also had an extra X chromosome; this might be another example of possible nonhomologous pairing in man.

Chromosome Aberrations↗
PubMed1985

Trichuris muris: structure and formation of the egg polar plugs.

The structure and development of the polar plugs of Trichuris muris eggs were observed by light and electron microscopy. Initial stages in plug formation commenced in the spermatheca of the adult female where two polar papillae became delimited from the remainder of the oocyte cytoplasm. These papillae exhibited a discrete PAS positive reaction and were regarded as prospective plug regions from which cytoplasmic granules were absent. Glycogen rosettes, initially concentrated in these prospective areas, were later transformed into an irregular fine network of chitin-protein microfibrils. This arrangement of microfibrils was in contrast to that of the surrounding collar region which displayed a distinct lamellate organization. The fully developed polar plug was of lower electron density than the shell. Each plug was covered externally by the vitelline layer and lined internally by the lipid layer of the eggshell.

Animals↗
PubMed1985

Human L-xylulose reductase variation: family and population studies.

Only one of the two main L-xylulose reductases present in human tissue is deficient in individuals with essential pentosuria (Lane, 1985). The isozyme which is affected by the pentosuria mutation occurs as mitochondrial and cytosolic forms in normal individuals, whereas the other isozyme (which is not affected by the mutation) occurs only in the cytosol. A new assay of red cell L-xylulose reductase activity has facilitated the identification of carriers of the essential pentosuria allele at both family and population levels. Reinvestigation of a Lebanese family in which pentosuria has previously been thought to be dominantly inherited reveals that the condition is recessively inherited in this family as well. A minimum estimate of the frequency of the pentosuria allele in an Ashkenazi-Jewish population, calculated from the apparent heterozygote frequency, is 0.0127. The likelihood of the Ashkenazi and Lebanese pentosuria alleles being the same is discussed.

Alleles↗
PubMed1985

Dental caries and blood groups in South African blacks.

DMFT scores were determined in series of 1) urban Black adolescents (132 boys, 143 girls) aged 16-18 yr, and 2) rural Black mothers (480) aged 20-35 yr. Each series was divided into upper and lower thirds, with respect to DMFT. No relationship was apparent between segments with good versus inferior teeth, and blood groups.

ABO Blood-Group System↗
PubMed1985

Short rib-polydactyly syndrome: a single or heterogeneous entity? A re-evaluation prompted by four new cases.

Four cases of lethal short rib-polydactyly syndrome (SRPS) from three non-consanguineous families are described. Radiological features were similar in all four cases and were most consistent with type III SRPS (Verma-Naumoff syndrome), but many differences in external and systemic abnormalities were noted. The considerable overlap of supposedly distinctive features displayed by the three main forms of SRPS is suggestive of a single locus mutation with variable expressivity, particularly for types I and III, possibly related to different mutant alleles and secondary intrauterine modification of the phenotype. All four cases showed anomalous sexual development. In spite of testicular differentiation in all four and a 46, XY karyotype in the two on whom chromosome studies were done, two infants were phenotypic females and two had ambiguous genitalia. A definitive diagnosis of SRPS was made at 26 weeks' gestation in a pregnancy at risk.

Chromosome Mapping↗
PubMed1985

Homozygosity for the delta-chain variant haemoglobin A2' (HbB2) (delta 16 Gly----Arg).

A healthy 20-year-old woman, belonging to the Kgalagadi tribe of Botswana, has been found to possess a variant Haemoglobin A2 as her only minor haemoglobin component. Fingerprinting and amino-acid analysis have shown that it is Haemoglobin A2' (delta 16 Gly----Arg). The one parent available for study is heterozygous for the Hb delta A2' allele and the variant haemoglobin accounts for 3% of the total haemoglobin in the proband. It is reasoned that the proband is, therefore, homozygous for the Hb delta A2' allele. No haematological abnormalities were evident.

Adult↗
PubMed1984

Waardenburg syndrome in South Africa. Part II. Is there founder effect for type I?

Three South African families of Afrikaner descent with the Waardenburg syndrome (WS) type I have been traced back for 12 generations. The families may be related through a French Huguenot couple who came to the Cape in 1683. Although the number of families in this study is small and the information incomplete and, although the earliest known family member with WS was born in 1842, the findings suggest that founder effect for the gene for WS type I may possibly exist in the Afrikaner population of South Africa.

Abnormalities, Multiple↗
PubMed1984

Waardenburg syndrome in South Africa. Part I. An evaluation of the clinical findings in 11 families.

The clinical findings in 11 families with 52 members affected with the Waardenburg syndrome (WS) are presented and compared with the findings from other studies. The families are assigned to WS type I (7 families containing 31 affected individuals), or type II (4 families with 21 affected members), depending on the presence or absence of dystopia canthorum, and the differences between the two types are discussed. The hypothesis that the features of WS are explicable on the basis of a neural crest defect is supported. Attention is drawn to the finding of spina bifida in 2 unrelated WS type I patients, and of delayed milestones or poor school performance necessitating special schooling in 9 different unrelated patients. Deafness has previously been considered to be the most disabling characteristic of the condition, but if there is an increased incidence of spina bifida or mental retardation associated with WS, the approach to genetic counselling might need to be altered.

Abnormalities, Multiple↗
PubMed1984

Antenatal diagnosis of sickle-cell anaemia by means of DNA restriction analysis.

Prenatal diagnosis by restriction enzyme analysis is now available in South Africa for globin-related disorders. An Indian couple at risk for sickle-cell anaemia requested prenatal diagnosis which was carried out by restriction enzyme analysis of DNA from cultured amniotic cells. In the case of the sickle-cell mutation a restriction enzyme, Mst II, is available for direct detection of the mutant gene. Mst II together with linked restriction fragment polymorphisms were used to make the diagnosis in this family. The fetus was found to be homozygous for the normal allele and this was confirmed postnatally by placental DNA analysis.

Amniocentesis↗
PubMed1984

Amniotic band syndrome and conditions simulating disruption malformations.

Twelve cases of fetal malformation due to the amniotic band syndrome (ABS) or disruption sequence were reviewed; these included craniofacial malformations, limb defects and gastroschisis. No one case was similar to another. The initial diagnosis was correct in 5 of the 12 cases, mainly those involving limb defects. All 4 cases in which major malformations were present were initially diagnosed incorrectly. The importance of correct diagnosis mainly concerns counselling regarding the future risk of recurrence--the probability of familial recurrence of ABS is very low, whereas the risk of recurrence of a familial neural tube defect is about 5%.

Amniotic Band Syndrome↗
PubMed1984

The Aarskog (facio-digital-genital) syndrome in South Africa. A report of three families.

Aarskog's syndrome comprises facial, digital and genital anomalies associated with short stature. Six affected males from three families were examined, and their clinical features are discussed. The presence of cleft lip in 1 of the patients supports the suggestion that cleft lip and cleft palate may well be a feature of the syndrome. Analysis of the pedigrees of the three families supports an X-linked recessive mode of inheritance with minimal expression in female carriers. The ultimate prognosis for affected individuals is good.

Abnormalities, Multiple↗
PubMed1984

Transition from a hunter-gatherer to a settled lifestyle in the !Kung San: effect on iron, folate, and vitamin B12 nutrition.

In 1969 a group of hunter-gatherer San were studied (Am J Clin Nutr 1971;24:229-42). Their state of hematological nutrition was excellent with a negligible incidence of iron, folate, or vitamin B12 deficiency. A genetically and linguistically similar San community who have been settled for the past 15 yr were the subjects of the present study. Anemia, due in the main to iron and/or folate deficiency, has become more common. Alcoholism has become rife in both sexes and all age groups. Our findings show that a settled lifestyle has resulted in a significant deterioration in the San's hematological nutrition.

Adolescent↗