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Biomedical subjects

G J te Meerman

Publications and source records attributed to G J te Meerman.

At least 55 records · Page 3Linked to original sources
PubMed1992

Birth and population prevalence of Duchenne muscular dystrophy in The Netherlands.

Mutations causing Duchenne muscular dystrophy (DMD) have a short survival. Therefore, birth and population prevalence are maintained by new mutations. The present inventory was made to estimate the birth and population prevalence rates of DMD in the Netherlands. Seven methods of case identification were used. Data on 496 definite, probable or possible DMD patients born since 1961, or alive on January 1, 1983, were obtained. Several methods gave an estimated ascertainment of more than 95%. The prevalence rate at birth of DMD was estimated at 23.7 x 10(-5) (1:4215) male live births (MLB) yearly. The prevalence rate in the male population on January 1, 1983 was 5.4 x 10(-5) (1:18496). About 1% of the males in this study may have autosomal recessive Duchenne-like muscular dystrophy. Until now there has been no convincing evidence for geographic differences in DMD prevalence at birth. A list of frequency studies of Duchenne muscular dystrophy is included. The DMD mutation rate calculated by the indirect method is 7.9 x 10(-5) genes per generation. However, this may well be an over-estimate, as this method does not account for germline mosaicism. Using a modified sex ratio method the proportion of sporadic DMD among all cases was estimated to be 0.106 (range 0-0.332). High frequency of germline mosaicism in DMD is a likely cause for the apparent lack of sporadic cases as found in previous studies, if mutation rates in male and female gametes are equal. Therefore, methods for estimating the proportion of new mutants in DMD should take germline mosaicism into account. The modified sex ratio method allows incorporation of data on germline mosaicism if available.

Cohort Studies↗
PubMed1991

Family distances as a measure of hidden consanguinity. A reappraisal.

We compared the family distances of patients with autosomal recessive disorders with those of a random control group and a matched control group. Only in the great-grandparental generation were weak-significant differences found. We also found that the family distances of persons with an urban origin were significantly larger than those of persons with a rural origin. In our study, family distance seems to be a more powerful measure of hidden consanguinity than the parental distance.

Chromosome Aberrations↗
PubMed1990

[Indications for an increased risk of neural tube defects in pregnancies following ovulation induction and (or) in-vitro fertilization].

Several authors have reported a possible association between IVF or induction of ovulation on the one hand and the occurrence of neural tube defects on the other hand. Here a review is given of recent literature on this subject, including data available from The Netherlands. Collaborative epidemiologic studies are needed to evaluate the potential risks. In individual pregnancies prenatal examination is advised. In spontaneous abortions fetal pathological evaluation is desirable.

Abortion, Spontaneous↗
PubMed1990

Close linkage of the Wilson's disease locus to D13S12 in the chromosomal region 13q21 and not to ESD in 13q14.

Wilson's disease (WD) is an autosomal recessive disorder resulting in copper accumulation notably in liver and brain tissue. Linkage of the WD locus (WND) to ESD at 13q14 was first shown by studies in families of Middle Eastern origin using the isozymic polymorphism of esterase D. Using RFLPs detected by the ESD cDNA we could not confirm this reported close linkage in an analysis of 17 WD families of northwest European origin. A tight linkage was detected, however, to the marker D13S12, located more distally at 13q21. No obligate cross-overs were detected in 63 gametes informative for this marker. Our data confirm an assignment of WND to 13q14-21. Its localization, however, seems to be more distal to ESD than previously reported. Although genetic heterogeneity cannot be excluded, the observed differences between the two populations are probably due to random variation.

Carboxylesterase↗
PubMed1990

Chromosomal damage in peripheral blood lymphocytes of patients treated for testicular cancer.

We describe the presence of a large number of chromosome aberrations in lymphocytes of 50 patients with testicular cancer. These chromosomal aberrations were not only found in patients treated with chemotherapy but also in untreated patients or in patients after surgery alone. Our results suggest a role for genetic instability in the pathogenesis of testicular cancer. This instability might be a risk factor for the development of secondary malignancies.

Adult↗
PubMed1990

Frequency of the delta F508 mutation and XV2c,KM19 haplotypes in cystic fibrosis families from The Netherlands: haplotypes without delta F508 still in disequilibrium.

We have determined the frequency of the major cystic fibrosis (CF) three base pair deletion (delta F508) mutation in 152 CF chromosomes from patients originating from the northern part of The Netherlands. In these patients, the deletion represents approximately 76% of CF mutations. Meconium ileus is strongly associated with homozygosity for the delta F508 mutation. The XV2c,KM19 haplotypes on the CF chromosomes without the delta F508 mutation are in disequilibrium with the population frequency, although showing an increased frequency of the 1 2 haplotype. The surplus of this haplotype is almost entirely made up by the pancreatic insufficient patients.

Cystic Fibrosis↗
PubMed1990

Pathogenesis of adult testicular germ cell tumors. A cytogenetic model.

In essence, two models exist of the pathogenetic relationship between seminomas and nonseminomatous germ cell tumors (NSGCTs). In the first model, the histogenesis of seminomas is assumed to diverge from that of the other testicular germ cell tumors (TGCTs) at an early stage. The neoplastic pathway of seminomas and NSGCTs is different, with limited or no crossover. The second model suggests that seminomas and NSGCTs have a common origin with a single neoplastic pathway on which seminomas are an intermediate stage in development of NSGCTs. Our data on the cytogenetics and ploidy of seminomas, combined tumors, and NSGCTs lend support to the model of pathogenesis of seminomas and NSGCTs in which all TGCTs (with the possible exception of spermatocytic seminoma and infantile yolk sac tumor) have a single origin and neoplastic pathway, with seminomas representing an intermediate stage in development of NSGCT components, as opposed to the model in which seminomas and NSGCTs develop separately. The progression of TGCTs probably proceeds from high to lower numbers of chromosomes and is therefore accompanied by a net loss of chromosomal material. This decrease will be the end result of loss of specific chromosomes, gain of some other chromosomes (or part of chromosomes), and development of structural abnormalities.

Carcinoma in Situ↗
PubMed1989

Chromosomal changes in mature residual teratomas following polychemotherapy.

A cytogenetic analysis of 13 mature residual teratomas following chemotherapy revealed modal chromosome numbers ranging from 52 to 85, in agreement with the flow cytometric determination of the DNA content of the tumors. At least one copy of an i(12p) was present in 12 tumors. One tumor, however, lacked that marker. The comparison between the chromosomal abnormalities found in mature residual teratomas following chemotherapy and those from primary testicular nonseminomas suggests that residual teratomas result from selection of clones from the primary tumor with a less abnormal karyotype.

Adult↗
PubMed1989

Cytogenetic analysis of ten human seminomas.

A cytogenetic analysis of ten seminomas has been carried out after direct harvesting of the tumor cells. Modal chromosome numbers ranged from 63 to 112. These numbers were in agreement with flow cytometric determination of the DNA content of the tumors. Eight tumors had at least one copy of an i(12p) among other chromosomal abnormalities. Two seminomas lacked the i(12p).

Adult↗
PubMed1989

Development of multiple endocrine neoplasia type 2A does not involve substantial deletions of chromosome 10.

In MEN2A both familial and sporadic cases are known. The familial cases show a dominant pattern of inheritance. In these respects, MEN2A resembles other tumors in whose etiology so-called tumor suppressor genes play a decisive role. The MEN2A locus has been assigned to chromosome 10 by linkage studies. Analysis of tumor DNA from 42 patients shows that markers on chromosome 10 were lost in only one tumor. Thus, these results contrast with previous studies which show that tumor development is generally associated with the loss of the whole or substantial parts of the chromosome on which the putative tumor suppressor gene is located.

Carcinoma↗
PubMed1989

Survival and clinical outcome in patients with cystic fibrosis, with or without neonatal screening.

After an experimental neonatal screening program for cystic fibrosis had been carried out in the Netherlands during 1973 to 1979, a follow-up study to evaluate the effects of neonatal screening was started in 1980. Although before 1980 the management of patients with cystic fibrosis was partly left to local hospitals, from the start of the follow-up program all patients in the study received similar treatment. A cumulative survival rate, calculated with exclusion of the patients with meconium ileus, showed at the age of 11 years a significantly better survival rate (p less than 0.05) for the 19 patients from the screened population (88%) than for the 25 patients from the nonscreened population (60%). Clinical condition was assessed on entry and at the age of 9 years in 16 screened and 20 nonscreened patients. On entry, comparison showed significantly better chest radiograph scores for the screened patients but no other significant differences. At the age of 9 years, after several years of similar treatment for all patients in the study, significantly better clinical (p less than 0.02) and chest radiograph scores (p less than 0.01), lower IgG levels (p less than 0.05), and higher vitamin A levels (p less than 0.01) were observed in the screened patients. Our study results suggest that early diagnosis and appropriate treatment may prevent serious deterioration and death at a young age, and may reduce the extent of early irreversible lung damage in patients with cystic fibrosis.

Albumins↗
PubMed1989

Linkage analysis of families with hereditary retinoblastoma: nonpenetrance of mutation, revealed by combined use of markers within and flanking the RB1 gene.

Nonpenetrance of the inherited mutation responsible for retinoblastoma has been reported. By DNA analysis in families with hereditary retinoblastoma, it is possible to identify healthy individuals in whom the mutation is nonpenetrant. This requires the use of DNA markers both within and flanking the retinoblastoma gene. We have analyzed the segregation of several markers in 19 families (69 meioses) with hereditary retinoblastoma. In two families a carrier was identified who showed nonpenetrance of the mutation predisposing to retinoblastoma. The intragenic markers were informative in 15 pedigrees. The use of flanking markers from the same chromosomal region caused an increase of the number of informative families to 18. No crossing-over within the gene was observed. In one family an inherited deletion involving one of the RB1 alleles was detected. Our findings emphasize the use of a combination of both intragenic and flanking markers to obtain both the highest reliability of carrier detection in families with hereditary retinoblastoma and an accurate estimate of the frequency of nonpenetrance.

Chromosome Deletion↗