摘要:

Recently, results have been presented which suggest that placental alkaline phosphatase (PLAP) is an IgG receptor, and that the transplacental transport of IgG from mother to fetus is dependent on the fetal PLAP genotype. In order to confirm the relationship between the PLAP types and transplacental IgG transport, we studied fetal (cord serum) IgG levels in relation to PLAP types, quantitative variations in PLAP activity, maternal IgG levels and gestation length. Fetal IgG levels and the fetal/maternal IgG ratio showed no significant correlation with PLAP types and PLAP activity. Thus differences between PLAP types with respect to transplacental IgG transport are unlikely to play a selective role in the maintenance of the PLAP polymorphism. In accordance with results from previous studies, significant correlations were found with maternal IgG levels and gestation length. Perusal of the literature suggests that PLAP is mainly an IgG1 receptor.

ISSN:0001-5652    

DOI:10.1159/000154247

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Mutation G551D of exon 11 of the cystic fibrosis transmembrane conductance regulator gene is one of the most common mutations in patients of European origin. In order to test the hypothesis that the mutation is identical by descent in these patients, we have studied haplotypes for the three intragenic microsateUite markers IVS8CA, IVS17bTA and IVS17bCA from 92 patients bearing this mutation, who had been referred to laboratories in Ireland, Scotland, England, France (Brittany) and the Czech Republic. In all cases we found that only haplotype 16-7-17 is associated with mutation G551D. Our results support the hypothesis of identity by descent of all cystic fibrosis chromosomes bearing mutation G551D in these patient populations, and suggest that given the combined mutation rate of the microsateUite markers, there is a low probability (p < 0.05) that the haplotype where mutation G551D first occurred remained unaltered for more than 170 generations.

ISSN:0001-5652    

DOI:10.1159/000154249

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The affected-pedigree-member (APM) method of linkage analysis is a nonparametric statistic for testing for nonindependent segregation of a marker to affected members of a pedigree. We present here results of a simulation study evaluating the power of the APM method to detect linkage. We have systematically explored, by computer simulation, the effect of a variety of factors on the power to detect linkage using the single-locus APM statistic. These factors include mode of inheritance, marker polymorphism, the distance between marker and disease, phenocopy rate, heterogeneity, and misspecified marker allele frequencies. We also evaluated the relative power obtained under fixed-structure sampling and sequential sampling. For a dominant disease, sequential sampling led to increased power as compared to fixed-structure sampling, while for a recessive disease, there was no clear advantage in sampling beyond nuclear families.

ISSN:0001-5652    

DOI:10.1159/000154250

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The affected-pedigree-member (APM) method of linkage analysis detects linkage by testing for increased marker similarity between affected individuals in a pedigree. Thus, the APM method poses a ‘one-locus’ question about the inheritance of the marker; it requires and makes no assumptions about the inheritance of the disease. It only requires that one be able to accurately determine who is affected. Since the APM method is model free, it is an important tool in testing for linkage of genetically complex diseases for which it is difficult to determine or define an accurate genetic model. In addition, the APM method may be used as a model-free confirmatory test to complement traditional lod score analyses. The X-linked version of the APM method developed here now permits researchers to apply this method to test for linkage of complex diseases to X-linked mark

ISSN:0001-5652    

DOI:10.1159/000154251

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Allele and genotype frequencies for six polymerase chain reaction (PCR)-based DNA genetic markers were determined in a Chinese sample population. The loci are HLA-DQα, low-density-lipoprotein receptor, glycophorin A, hemoglobin γG, D7S8, and group-specific component. These results were obtained using the AmpliType® HLA-DQα forensic DNA amplification and typing kit and the AmpliType PM PCR amplification and typing kit. All loci met Hardy-Weinberg expectations and there was no evidence for association of alleles between the loci. The frequency data can be used in forensic analyses and paternity tests to estimate the frequency of a DNA profile in the Chinese populat

ISSN:0001-5652    

DOI:10.1159/000154252

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The genetic basis for colorectal cancer was investigated by complex segregation analysis of a published series of 305 pedigrees ascertained through a large population database. Two hundred and five of the pedigrees were ascertained through patients diagnosed with colorectal cancer before age 55, and 100 from patients diagnosed with colorectal cancer between the ages of 55 and 74. The analysis was carried out using the program POINTER. Using the joint-likelihood approach, the familial aggregation of colorectal cancer was compatible with the inheritance of a dominant gene. The gene frequency of the putative abnormal allele was 0.002 with a lifetime penetrance of 85%. However, under conditional likelihood, this mode of inheritance for a major gene was not favoured. The possible aetiologies of this paradoxical finding are discussed.

ISSN:0001-5652    

DOI:10.1159/000154253

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Nine multiplex schizophrenia families were genotyped with seven highly polymorphic microsatellite loci used in the construction of an index map of chromosome 21. Assuming either autosomal dominant or recessive transmission, evidence of linkage was not found. In addition, the nonparametric sib-pair test did not yield significant evidence of linkage.

ISSN:0001-5652    

DOI:10.1159/000154254

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0001-5652    

DOI:10.1159/000154255

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

We tested the frequency of the ΔF508 mutation and haplotypes linked to the cystic fibrosis (CF) gene in Cuba. The ΔF508 deletion was detected in 34.0% of the CF chromosomes. There was a shortage of ΔF508 heterozygotes, suggesting non-randomness in mating patterns. Haplotype B (XV2C/KM19 1/2) was found on 40.5% of the CF chromosomes (71.5% of ΔF508 chromosomes, 28.3% of non-ΔF508 CF chromosomes) against 13.5% of non-CF chromos

ISSN:0001-5652    

DOI:10.1159/000154256

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Among 1,239 unrelated adults from Upper Silesia (Poland), a significant association between ESD and C3 phenotypes was found. This is in accordance with the results obtained in an Indian population.

ISSN:0001-5652    

DOI:10.1159/000154257

出版商:S. Karger AG    

年代:1995

数据来源: Karger