[Pre-symptomatic diagnosis of Huntington disease by polymerase chain reaction]. / Polimeráz láncreakción alapuló praesymptomás diagnózis huntington-betegségben.

The authors are reporting on the presymptomatic diagnosis of the autosomal dominant Huntington's disease applying the polymerase chain reaction for the first time in Hungary. The detection of the products yielded by polymerase chain reaction was carried out by silver stained polyacrylamide gel. This silver staining gave appropriate result without using radioactive technique. Cause of the disease is the greater number of CAG repeat sequence in the region of the Huntington's disease gene. The number of CAG repeats in Huntington patients is more than 37, while in not affected persons it is less than 34. Four members of two families each were examined and presymptomatic diagnoses were performed in two cases of both families. Normal alleles were detected in all cases. The tests supported the diagnoses of these patients suffering of clinically proved Huntington's disease.

[Prenatal diagnosis of cystic fibrosis by mutational analysis]. / A cystikus fibrosis praenatalis diagnosztikája mutáció analízissel.

The authors give a review about the latest method of the prenatal diagnosis of cystic fibrosis. Examples were chosen from their own cases to illustrate the possibilities of the prenatal diagnosis based on the mutation analysis of the CFTR gene. Using both mutation and haplotype analysis, 10 prenatal diagnosis were performed from chorionic villus samples taken in the early stage of the pregnancy (10-12 weeks). There were 5 healthy and 5 affected fetuses found. The advantage of this method, that in certain cases, diagnosis is available for families having no live affected child.

The occurrence of various non-delta F508 CFTR gene mutations among Hungarian cystic fibrosis patients.

Cystic fibrosis (CF) is an autosomal recessive disease caused by different mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The frequency of the major mutation (delta F508) in the Hungarian population is 64%. To identify other common mutations in CF families from Hungary, 30 non-delta F508 CF chromosomes were analyzed for selected mutations in exon 11 (G551D, R553X, G542X), intron 4 (621 + 1G----T), intron 10 (1717-1G----A), exon 20 (W1282X), and in exon 21 (N1303K) of the CFTR gene. In 6 of the 30 non-delta F508 CF chromosomes the following mutations were detected: R553X, G542X, 1717-1G----A, W1282X, and N1303K. After analysis of the above eight mutations, 30% of CF chromosomes are as yet undefined and further analysis is planned.

Molecular analysis of cystic fibrosis in the Hungarian population.

Hungarian cystic fibrosis (CF) families (n = 33) including 114 family members have been analysed for the presence of the delta F508 mutation within the cystic fibrosis transmembrane conductance regulator (CFTR) gene, and have been haplotyped with probes for restriction fragment length polymorphisms (RFLPs) known to be linked to the CFTR gene. The delta F508 deletion was present in 64% of CF chromosomes. As in many other populations, linkage disequilibrium was found between the CF locus and the haplotype B (XV-2c: allele 1, KM-19: allele 2), which accounts for 95% of delta F508 CF chromosomes in our families.

[Experience with chorionic villi sampling]. / Tapasztalataink chorionboholy-mintavétellel.

The authors discuss their experiences from 412 chorion villus samplings, (CVS), which they have done under four and a half years since 1985. They used eight types of instruments in performing their examinations and each instrument proved to be satisfactory in the gaining of chorion villus samples, suitable for further tests. They also discuss the bacteria found most frequently in the vagina on the basis of the examination and culturing of both vaginal and cervical fluid done prior to 151 CVS examinations and the effective method with which ascending infection can be prevented. They discuss a distributional pattern of their results based on the different indications for the CVS examinations, and the outcome of each of the pregnancies after CVS. In 377 cases they did direct karyotyping, in 30 cases DNA examination and in five cases enzyme determination also occurred.

Identification of Y-chromosomal DNA in a Turner syndrome mosaic by polymerase chain reaction.

A 15.5-year-old female was referred for primary amenorrhea and slow development of secondary sex characteristics. The karyotype revealed 45,X/46,X,+mar (75%/25%). The small marker chromosome was C-band and Q-band negative. It appeared to be primarily centromeric with some light G-band staining material on either side. Females with Y-chromosomal material are at an increased risk for gonadal neoplasia and this patient was studied further to investigate the possibility that the marker was a deleted Y chromosome. Polymerase chain reaction (PCR) analysis of this patient's DNA revealed the presence of Y-chromosomal material presumably derived from the marker chromosome. These results indicate that the PCR technique, in conjunction with cytogenetic analysis, can identify possible Y-chromosomal material. This testing provides critical information necessary for correct medical followup of Turner syndrome mosaic patients.

[Prenatal diagnosis of cystic fibrosis based on DNA analysis]. / A cysticus fibrosis DNS analízisen alapuló praenatalis diagnosztikája.

25 families at risk of having a child with cystic fibrosis have been counselled about prenatal diagnosis by the use of linked DNA probes (xV-2c, pCS.7, Met D, Met H, pJ3.11 and KM 19). In 20 families one or more informative probes, in 3 cases only partly informative probes were found, and in 2 families there was no informative probe at all. In 9 cases prenatal diagnosis have been performed, 6 children have been born and confirmed to be free from cystic fibrosis and 3 terminations were carried out because of prenatal prediction of cystic fibrosis.

[Possibilities of prenatal diagnosis in hemophilia A based on DNA analysis]. / Lehetöségek a haemophilia-A praenatalis diagnosztikájára DNS analízis alapján.

Haemophilia-A is the most common bleeding disorder in man, resulting from a deficiency of the coagulant protein, factor VIII. The factor VIII gene is located at Xq28 and the disease is inherited as an X-linked recessive disorder. There is a possibility using DNA probes closely linked to the gene factor VIII to determine the genotype. The availability of factor VIII DNA probes has led to the detection of carrier females and first trimester prenatal diagnosis of haemophilia-A. The authors give a short account on their experiences with four DNA probes. Their studies were carried out in nine families who have affected individuals and plan another pregnancies in the near future. DNA analysis can allow first trimester prenatal diagnosis from chorionic villi taken at 8-10th weeks of gestation. In the case of a male fetus it is possible to determine whether the mutant gene is inherited or not. Till now seven prenatal diagnoses have been performed based on the chorionic DNA.

[Prenatal diagnosis of Hunter's disease]. / Hunter-betegség (MPS--II) praenatalis felismerése.

The authors give a short report about the first-trimester prenatal detection of Hunter's disease (MPS II) inherited as X-linked disorder. There is written about a family having one affected child with Hunter's syndrome. Chorionic villus sample was taken at 10th weeks of gestation in the new pregnancy of the mother. The sex of the fetus was a male determined by DNA analysis. The activity of sulphoiduronate sulphatase was very low. The enzyme activity was also extremely low in the cultured cells from amniotic fluid taken at 16th weeks of gestation. On the basis of these results the pregnancy was terminated at parents's request. The diagnosis of Hunter's disease was confirmed by measuring the enzyme activity of the cultured fibroblasts from the male fetus.

First trimester chorionic villus sampling for DNA analysis.

Early prenatal diagnosis of cystic fibrosis (CF) has become possible after the identification of linked DNA markers on chromosome 7. Chorionic villus sampling (CVS) has made possible the first-trimester prenatal diagnosis of CF. We report our experience of 336 pregnant women between 8-12th week. Six different types of sampling devices have been used to get chorionic tissue. Our results proved that the quantity and the quality of the sample gained was the same irrespective of the method employed in obtaining them.

First trimester diagnosis of cystic fibrosis with linked DNA probes.

In late 1985 the cystic fibrosis (CF) gene was located to chromosome 7, at 7q 22/31. Several restriction fragment length polymorphism (RFLP) markers are closely linked to the CF gene. These markers permit accurate first-trimester prenatal diagnosis based on analysis of chorionic villus DNA by studies of families with one or more affected children. In our laboratory 13 families at risk of having a child with CF have been counselled by the use of linked DNA probes: xV-2c; pCS.7; Met H; Met D; pJ3.11; KM 19. In all cases one or more of the mentioned probes were sufficiently informative to allow first-trimester prenatal diagnosis. In four of the 13 families tested prenatal diagnosis have been performed.

[Sex determination of the embryo by DNA studies of chorionic villi samples]. / Az embryo nemének meghatározása chorionboholy-mintából DNS vizsgálattal.

The first step in the prenatal diagnosis of X-linked genetic disorders is the determination of the sex of the fetus. A new method for this purpose is based on recombinant DNA technology. The authors give a short account on their experiences with a Y specific DNA probe. Fetal DNA was prepared from chorionic villi taken at the 8th-12th weeks of gestation. The DNA was hybridised with the Y specific probe. This probe was isolated from the 3,4 kilobase human repeat sequence derived from heterochromatin of the Y chromosome and had 1000 times more affinity for male DNA than for female DNA. The method based on hybridisation with the Y specific probe should facilitate first-trimester prenatal sex determination of X-linked genetic disorders.