Molecular and clinical findings in Austrian cystic fibrosis patients with mutations in exon 11 of the CFTR gene.

In order to determine the heterogeneity of mutations in exon 11 of the cystic fibrosis transmembrane conductance regular (CFTR) gene in Austrian cystic fibrosis (CF) patients, we analysed 207 non-delta F508 chromosomes by direct sequencing of PCR-amplified genomic DNA. A total of four previously described point mutations present on 14/207 (6.8%) non-delta F508 chromosomes were detected: G542X, G551D, R553X, and R553Q. The second CF mutation was delta F508 in most patients, W1282X (a nonsense mutation in exon 20) in one and a currently unknown non-delta F508 mutation in another case. One patient was documented to be homozygous for G542X. The proportion of non-delta F508 chromosomes among total CF chromosomes is 45% in Austria and 32% in the world population. In our population the mutations G542X, G551D, and R553X were found on 3.9% (1.7%), 1.9% (0.9%) and 0.5% (0.2%) of non-delta F508 chromosomes (of total CF chromosomes), respectively. The average worldwide frequencies of these mutations are higher: 7.1% (2.4%), 4.8% (1.6%), 2.1% (0.7%) of non-delta F508 chromosomes (of total CF chromosomes screened), respectively. A comparison of the allele frequencies in Austria with those detected in neighbouring countries reveals some notable differences. In a subsequent retrospective analysis we found that all nucleotide changes, identified by direct sequencing, can be detected by denaturing gradient gel electrophoresis (DGGE). The lack of any false positive or false negative result suggests that DGGE is a convenient and reliable screening method for point mutations.

[Immunomodulator action of living, nonpathogenic Enterococcus faecalis bacteria from humans]. / Immunmodulatorische Wirkung lebender nicht-pathogener Enterococcus faecalis-Bakterien des Menschen.

Immunomodulating Effect of Living Nonpathogenic Enterococcus faecalis Originated from Humans Symbioflor 1 is a pharmaceutical preparation, consisting of a suspension of living nonpathogenic Enterococcus faecalis (E. faecalis). The effect on the liberation of cytokines of E. faecalis was investigated in in-vitro experiments with human peripheral mononuclear blood cells revealing the following results: 1. E. faecalis stimulates the liberation of interleukin 1 (IL-1 beta) and interleukin-6 (IL-6) in a dose-dependent manner; the E. faecalis induced liberation of IL-1 beta and IL-6 is inhibited by dexamethasone (Dm) but not by cyclosporin A (CsA). 2. E. faecalis stimulates the liberation of gamma-interferon (IFN-gamma) in a dose-dependent manner, which is inhibited by both Dm and CsA. 3. Phytohemagglutinin (PHA)-induced liberation of gamma-IFN and interleukin-2 (IL-2) is inhibited by E. faecalis in a dose-dependent manner. The relevancy to clinical trials of the in vitro results is discussed.

A sporadic form of hereditary neuropathy with liability to pressure palsies: clinical, electrodiagnostic, and molecular genetic findings.

We report a patient who had episodes of recurrent peripheral nerve pressure palsies. Electrodiagnostically, we found a clear decrease of nerve conduction velocity in affected and unaffected nerves. All the patient's relatives showed entirely normal clinical and electrodiagnostic findings. Histopathologically, there were extensive irregularities of the myelin sheaths with numerous tomaculous swellings. DNA analysis revealed a deletion for probes flanking the PMP-22 gene at the maternal chromosome 17 in our patient. His mother showed a normal gene dosage for all markers deleted in our patient, indicating a new mutation.

A new missense mutation G126D in exon 4 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

Cystic fibrosis (CF) is the most common severe autosomal recessive disorder in the Caucasian population. Beside the major mutation delta F508, which accounts for approximately 68% of all CF chromosomes, more than 350 different point mutations leading to this disease have been detected and communicated to the 'Cystic Fibrosis Genetic Analysis Consortium'. As these mutation are scattered about the whole CFTR gene we used denaturing gradient gel electrophoresis as a rapid method for screening a large number of CF patients for point mutations in the CFTR exons.

[Molecular genetic diagnosis of Wiskott-Aldrich syndrome]. / Molekulargenetische Diagnostik beim Wiskott-Aldrich-Syndrom.

BACKGROUND/AIMS: Wiskott-Aldrich syndrome is a severe X-linked recessive disorder of the hematopoietic system. The gene locus for Wiskott-Aldrich syndrome was mapped on the proximal short arm of the X chromosome by demonstrating close linkage to the loci DXS255 and TIMP. Carriers for Wiskott-Aldrich syndrome are asymptomatic and, hence, can not be identified clinically. METHODS: For a better estimate of the carrier risk of female family members, an extended molecular genetic analysis has been carried out on two kindreds with Wiskott-Aldrich syndrome: We followed the allele segregation at the two marker loci mentioned above known to be closely linked to the disease locus (indirect genotype diagnostics); in addition, we determined the pattern of X-inactivation by analyzing the methylation status of the two X chromosomes. RESULTS: We show that carriers for Wiskott-Aldrich syndrome can reliably be identified by the combination of segregation and X chromosome inactivation studies. Helpful information can be obtained by such studies in sporadic cases, too, or in families, in which--due to the early death--no surviving affected males are available for an DNA study. CONCLUSION: Indirect genotype analysis combined with the study of X-inactivation pattern is a valuable diagnostic tool for genetic counselling of families with Wiskott-Aldrich syndrome.

Clinical and molecular analysis of five inv dup(15) patients.

Five patients with inv dup(15) chromosomes were investigated with molecular probes on proximal 15q to determine the parental origin and extent of the duplicated segment. Cytogenetic investigation showed that four patients carried one and a fifth patient had two extra chromosomes derived from number 15 in all cells. In situ hybridization with a chromosome 15 library and a centromere 15 probe confirmed that the entire inv dup chromosomes were derived from chromosome 15. Molecular analysis using probes mapping in the region deleted in Prader-Willi syndrome (PWS) and Angelman syndrome (AS) patients implied that in at least two patients the extra chromosomes were asymmetric with one copy of the PWS region on the extra marker chromosome but two copies of the region centromeric to the PWS region. Three other cases had an inv dup(15) with two extra copies of the PWS region, but in one of these, heteromorphisms clearly demonstrated that the two centromeres derived from two different chromosomes. The inv dup(15) presumably resulted from an illegitimate recombination event between two different chromosomes 15 in most or all of these cases. All patients showed a maternal origin of the duplicated chromosome. The clinical severity appears to be associated with dosage of the PWS/AS region rather than with differences in the extent of the duplicated segment.

Microdissection of a human marker chromosome reveals its origin and a new family of centromeric repetitive DNA.

A series of procedures including chromosome microdissection, sequence-independent PCR, Southern-blot-hybrid-selection-cloning and sequencing of microdissected DNA-library members were used to analyze DNA from a familial marker chromosome centromere and to determine the origin of the marker chromosome in the case of a live-born, tetraploid human infant. A new family of repetitive DNA, termed sn5 satellite, was sequenced and characterized by DNA hybridization. The sn5 satellite family appears to be primate-specific and shows a chromosome-specific distribution which parallels that of alpha satellite suprachromosomal family 2. This suprachromosomal classification is based on sequence similarity of centromeric alpha satellite DNA within particular groups of chromosomes. It has been postulated that the similarity of alphoid sequences within each of the three suprachromosomal families results from homologous exchanges between nonhomologous chromosomes within each family. The parallel distribution of sn5 satellite sequences at the centromeres of chromosomes of alphoid suprachromosomal family 2 suggests that homologous exchanges between non-homologous chromosomes may be the basis of simultaneous chromosome-specific sequence conservation for multiple centromeric satellite DNA families.

Mutation analysis of the iduronate-2-sulfatase gene in patients with mucopolysaccharidosis type II (Hunter syndrome).

Iduronate-2-sulfatase (IDS) cDNA from fibroblasts of nine patients with Hunter syndrome (mucopolysaccharidosis type II) was screened for mutations using single strand conformation polymorphism analysis. Direct sequencing revealed a number of different mutations including missense or nonsense point mutations, deletions of one, two, or 60 base pairs, and a 22 base pair-insertion. Mutations of these types probably account for most IDS gene defects as only about 20% of Hunter patients have a complete deletion or gross structural alteration of their IDS gene. Thus the broad clinical variability amongst the Hunter patients may be due to the extensive genetic heterogeneity seen. The relationship between genotype and clinical phenotype is analysed in 12 Hunter patients.

Frequency of delta F508 and haplotype association in Austrian cystic fibrosis families.

The frequency of the major mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene was analyzed for 113 Austrian cystic fibrosis (CF) patients. An overall frequency of 55% for delta F508 was found with values of 72% and 13% for patients with pancreatic insufficiency (CF-PI) and those with pancreatic sufficiency (CF-PS), respectively. Furthermore, the distribution of the alleles of the closely linked DNA markers XV2c/KM19/MP6d-9 in our families is described.

Uniparental origin of sex chromosome polysomies.

The parental origin of the additional sex chromosomes in 8 cases with high-order sex chromosome polysomies was determined using DNA polymorphisms. The additional sex chromosomes were paternally derived in 3 48,XXYY cases, and maternal in origin in 1 48,XXXY case and 4 49,XXXXY cases. Thus, all extra chromosomes, within a particular patient, were always derived from only one parent. Their most likely origin was successive nondisjunction at the first and second meiotic division in one germ cell. The mechanism involved remains unclear, but appears to be independent of parental ages.

Localization of genes and anonymous DNA probes on the short arm of chromosome 7.

We have previously described the cytogenetic analysis of two patients with Greig cephalopolysyndactyly syndrome (GCPS) and various microdeletions on the short arm of Chromosome (Chr) 7. Using genes and anonymous DNA probes from 7p we analyzed the DNA of our patients for loss of heterozygosity, or we determined the copy number by semi-quantitative Southern hybridization. We have been able to show hemizygosity for the genes of INHBA, IGFBP1 and GLI3 in both patients and therefore can give the chromosomal assignment 7p12.3-p13. CRI-R944 and CRI-P137 map to the same region, whereas CRI-S207 can be assigned to 7p13-p14.2; TM102L, TS93, TS194, TM77 and TN177 showed no change and these probes map distal to 7p14.2.

A somatic cell hybrid panel and DNA probes for physical mapping of human chromosome 7p.

To identify by reverse genetics genes on the short arm of human chromosome 7 expected to be involved in the regulation of human craniofacial and limb development, we have set up a human mouse somatic cell hybrid panel that divides 7p into 9 fragments. The breakpoints are defined by deletions or translocations involving one chromosome 7 in the cells of the human cell fusion partners. Particularly densely covered with these cytogenetic anchor points is the proximal area of 7p within and around 7p13. The number of cytogenetic mapping points within proximal 7p could be increased by four, using two diploid human cell lines with small interstitial deletions in this region for dosage studies. We used Southern blots of this panel to assign to 7q or subregions of 7p more than 300 arbitrary DNA probes or genes that provide reference points for physical mapping of 7p. Three reciprocal translocations with one of the breakpoints in 7p13 mark the location of a gene involved in Greig cephalopolysyndactyly syndrome. To define an area in which we could identify candidates for this developmental gene, we established a macrorestriction map using probes flanking the putative gene region. The Greig translocations were found to be located within a 630-kb NotI restriction fragment.

Whistling face syndrome. A case report and literature review.

The cranio-carpo-tarsal or "whistling face" syndrome was first described by Freeman and Sheldon in 1938. More than 60 cases with great variability of expression are known till now and autosomal dominant as well as recessive inheritance and sporadic cases suggest a genetic heterogeneity. We review 60 well-documented cases of the literature and present a patient with a severe form, who died of bronchopneumonia at the age of 9 months. The facial stigmata of his mother and the ulnar deviations of his maternal grandfather support the autosomal inheritance of the syndrome.

Molecular and cytogenetic analysis in two patients with microdeletions of 7p and Greig syndrome: hemizygosity for PGAM2 and TCRG genes.

Greig cephalopolysyndactyly syndrome (GCPS) is an autosomal dominant disorder that has been mapped to 7p13. We have investigated two patients with GCPS and a cytogenetically visible microdeletion of the short arm of chromosome 7 with gene probes that have been assigned close to the proposed Greig locus. Deletion breakpoints were determined from high-resolution G- and R-banded chromosomes. In patient BC with a de novo deletion (7p12.3-7p14.2) we have found a loss of the genomic region containing the T-cell receptor gamma (TCRG) gene cluster, whereas the other patient IR with a deletion (7p11.2-7p13) due to a de novo translocation was apparently normal for this region. Gene dosage analysis revealed a loss of the phosphoglycerate mutase muscular form (PGAM2) gene locus in both patients. Hox 1.4 and interferon-beta 2 (IFNB2) showed a normal gene dosage. Our investigations revealed the following ordering and assignments of the studied genes: PGAM2 and GCPS in 7p12.3-13; TCRG in the distal part of 7p13-7p14.2; Hox 1.4 and IFNB2 distal to 7p14.2. Our results suggest a location of the TCRG gene more proximal than that reported previously. Furthermore, we were able to exclude the Hox 1.4 gene from involvement in the pathogenesis of GCPS.