[Unilateral partial deferential agenesia and CFTR gene composite heterozygoty (deltaF508/V938G)]. / Agénésie déférentielle partielle unilatérale et hétérozygotie composite du gène CFTR (DeltaF508/V938G).

This is a case report of a thirty-year-old-man consulting for a primary infertility that was diagnosed four years ago. Andrologic exam was normal. Two spermograms found normal spermatic parameters. An uro-genital echography with a RMI showed that a unilateral agenesia of the left vas deferens in the pelvic portion. Then, a composite heterozygoty of the CFTR gene (DeltaF508/V938G) was found. This is the first time that the association of these two mutations has been described. This case also makes it possible to wonder about the need for realizing, or not, a systematic basis imagery (ultrasound examination in first), in the event of infertility of the couple. In this context, the discovery of an echographic anomaly made it possible to identify CFTR mutations, whose physiopathological implication in the infertility can be discussed (CFTR related disorders)...

GUG is an efficient initiation codon to translate the human mitochondrial ATP6 gene.

A maternally inherited and practically homoplasmic mitochondrial (mtDNA) mutation, 8527A>G, changing the initiation codon AUG into GUG, normally coding for a valine, was observed in the ATP6 gene encoding the ATPase subunit a. No alternate Met codon could replace the normal translational initiator. The patient harboring this mutation exhibited clinical symptoms suggesting a mitochondrial disease but his mother who carried the same mtDNA mutation was healthy. The mutation was absent from 100 controls and occurred once amongst 44 patients suspected of Leber Hereditary Optic Neuropathy (LHON) but devoid of typical LHON mutations. In patient fibroblasts, no effect of 8527A>G mutation could be demonstrated on the biosynthesis of mtDNA-encoded proteins, on size and the content of ATPase subunit a, on ATP hydrolysis and on mitochondrial membrane potential. In addition, ATP synthesis was barely decreased. Therefore, GUG is a functional initiation codon for the human ATP6 gene.

Use of denaturing HPLC and automated sequencing to screen the VMD2 gene for mutations associated with Best's vitelliform macular dystrophy.

We identified three novel VMD2 mutations in patients with Best's macular dystrophy. DHPLC analysis of the 11 VMD2 exons revealed abnormal profiles in exon 8. Direct sequencing showed that these abnormal profiles were due to monoallelic transitions and transversions. We also found three polymorphic sequence changes that have been reported previously and annotated to an online database (http://www.uni-wuerzburg.de/humangenetics/vmd2.html).

Identification of novel VMD2 gene mutations in patients with best vitelliform macular dystrophy.

ABSTRACT We report five novel VMD2 mutations in Best's macular dystrophy patients (S16F, I73N, R92H, V235L, and N296S). An SSCP analysis of the VMD2 11 exons revealed electrophoretic mobility shifts exclusively in exons 2, 3, 4, 6 and 8. Direct sequencing indicated that these shifts are caused by mono-allelic transition in exons 2, 4, 6, 8 and transversion in exons 3 and 6. Five novel "silent" polymorphisms are also reported: 213T>C, 323C>A, 1514A>G, 1661C>T, and 1712T>C. Hum Mutat 17:235, 2001.

Human airway mucin glycosylation: a combinatory of carbohydrate determinants which vary in cystic fibrosis.

Human airway mucins represent a very broad family of polydisperse high molecular mass glycoproteins, which are part of the airway innate immunity. Apomucins, which correspond to their peptide part, are encoded by at least 6 different mucin genes (MUC1, MUC2, MUC4, MUC5B, MUC5AC and MUC7). The expression of some of these genes (at least MUC2 and MUC5AC) is induced by bacterial products, tobacco smoke and different cytokines. Human airway mucins are highly glycosylated (70-80% per weight). They contain from one single to several hundred carbohydrate chains. The carbohydrate chains that cover the apomucins are extremely diverse, adding to the complexity of these molecules. Structural information is available for more than 150 different O-glycan chains corresponding to the shortest chains (less than 12 sugars). The biosynthesis of these carbohydrate chains is a stepwise process involving many glycosyl- or sulfo-transferases. The only structural element shared by all mucin O-glycan chains is a GalNAc residue linked to a serine or threonine residue of the apomucin. There is growing evidence that the apomucin sequences influence the first glycosylation reactions. The elongation of the chains leads to various linear or branched extensions. Their non-reducing end, which corresponds to the termination of the chains, may bear different carbohydrate structures, such as histo-blood groups A or B determinants, H and sulfated H determinants, Lewis a, Lewis b, Lewis x or Lewis y epitopes, as well as sialyl- or sulfo- (sometimes sialyl- and sulfo-) Lewis a or Lewis x determinants. The synthesis of these different terminal determinants involves three different pathways with a whole set of glycosyl- and sulfo-transferases. Due to their wide structural diversity forming a combinatory of carbohydrate determinants as well as their location at the surface of the airways, mucins are involved in multiple interactions with microorganisms and are very important in the protection of the underlying airway mucosa. Airway mucins are oversulfated in cystic fibrosis and this feature has been considered as being linked to a primary defect of the disease. However, a similar pattern is observed in mucins from patients suffering from chronic bronchitis when they are severely infected. Airway mucins from severely infected patients suffering either from cystic fibrosis or from chronic bronchitis are also highly sialylated, and highly express sialylated and sulfated Lewis x determinants, a feature which may reflect severe mucosal inflammation or infection. These determinants are potential sites of attachment for Pseudomonas aeruginosa, the pathogen responsible for most of the morbidity and mortality in cystic fibrosis, and the expression of the sulfo- and glycosyl-transferases involved in their biosynthesis is increased by TNFalpha. In summary, airway inflammation may simultaneously induce the expression of mucin genes (MUC2 and MUC5AC) and the expression of several glycosyl- and sulfo-transferases, therefore modifying the combinatory glycosylation of these molecules.

[Pendred's syndrome. Current features]. / Le syndrome de Pendred. Aspects actuels.

Introduction Pendred's syndrome is a recessive autosomal disease, traditionally defined as the association of deaf-mutism, goiter and dysfunctional iodide organization revealed by the perchlorate discharge test. It represents 4 to 10% of the causes of congenital hypoacusis. Although described more than a 100 years ago, the association of thyroid and cochleo-vestibular damage remained unclear for many years. Genetic abnormalities Progress in molecular biology has revealed that the disease is related to alterations in the PDS gene situated on chromosome 7. The PDS gene is responsible for the production of pendrine, protein involved in anion (l-, Cl-) transportation, notably in the apical pole of the thyreocyte and the cochlear duct, where the endolympha is produced. Practical implications The truncation of pendrine related to the genetic alterations be responsible for the morpho-functional alterations in the cochlear apparatus and the thyroid. In this perspective, Pendred's syndrome would appear as a genetic disorder in anion transportation.

Spectrum of CFTR mutations in cystic fibrosis and in congenital absence of the vas deferens in France.

We have collated the results of cystic fibrosis (CF) mutation analysis conducted in 19 laboratories in France. We have analyzed 7, 420 CF alleles, demonstrating a total of 310 different mutations including 24 not reported previously, accounting for 93.56% of CF genes. The most common were F508del (67.18%; range 61-80), G542X (2.86%; range 1-6.7%), N1303K (2.10%; range 0.75-4.6%), and 1717-1G>A (1.31%; range 0-2.8%). Only 11 mutations had relative frequencies >0. 4%, 140 mutations were found on a small number of CF alleles (from 29 to two), and 154 were unique. These data show a clear geographical and/or ethnic variation in the distribution of the most common CF mutations. This spectrum of CF mutations, the largest ever reported in one country, has generated 481 different genotypes. We also investigated a cohort of 800 French men with congenital bilateral absence of the vas deferens (CBAVD) and identified a total of 137 different CFTR mutations. Screening for the most common CF defects in addition to assessment for IVS8-5T allowed us to detect two mutations in 47.63% and one in 24.63% of CBAVD patients. In a subset of 327 CBAVD men who were more extensively investigated through the scanning of coding/flanking sequences, 516 of 654 (78. 90%) alleles were identified, with 15.90% and 70.95% of patients carrying one or two mutations, respectively, and only 13.15% without any detectable CFTR abnormality. The distribution of genotypes, classified according to the expected effect of their mutations on CFTR protein, clearly differed between both populations. CF patients had two severe mutations (87.77%) or one severe and one mild/variable mutation (11.33%), whereas CBAVD men had either a severe and a mild/variable (87.89%) or two mild/variable (11.57%) mutations.

The sialylation of bronchial mucins secreted by patients suffering from cystic fibrosis or from chronic bronchitis is related to the severity of airway infection.

Bronchial mucins were purified from the sputum of 14 patients suffering from cystic fibrosis and 24 patients suffering from chronic bronchitis, using two CsBr density-gradient centrifugations. The presence of DNA in each secretion was used as an index to estimate the severity of infection and allowed to subdivide the mucins into four groups corresponding to infected or noninfected patients with cystic fibrosis, and to infected or noninfected patients with chronic bronchitis. All infected patients suffering from cystic fibrosis were colonized by Pseudomonas aeruginosa. As already observed, the mucins from the patients with cystic fibrosis had a higher sulfate content than the mucins from the patients with chronic bronchitis. However, there was a striking increase in the sialic acid content of the mucins secreted by severely infected patients as compared to noninfected patients. Thirty-six bronchial mucins out of 38 contained the sialyl-Lewis x epitope which was even expressed by subjects phenotyped as Lewis negative, indicating that at least one alpha1,3 fucosyltransferase different from the Lewis enzyme was involved in the biosynthesis of this epitope. Finally, the sialyl-Lewis x determinant was also overexpressed in the mucins from severely infected patients. Altogether these differences in the glycosylation process of mucins from infected and noninfected patients suggest that bacterial infection influences the expression of sialyltransferases and alpha1,3 fucosyltransferases in the human bronchial mucosa.

[Correlation of genitourinary abnormalities, spermiogram and CFTR genotype in patients with bilateral agenesis of the vas deferens]. / Corrélation entre anomalies génito-urinaires, spermogramme et génotype CFTR chez les patients atteints d'une agénésie bilatérale des canaux déférents.

OBJECTIVES: To evaluate the frequency of urogenital ultrasound and spermatic abnormalities in patients with bilateral vas deferens agenesis according to the presence or absence of CFTR gene mutation. METHODS: In 41 patients with bilateral vas deferens agenesis confirmed by surgical exploration between 1988 and 1997, renal and seminal vesicle anomalies were investigated by ultrasonography. Spermatic parameters (pH, fructose and ejaculate volume) were also studied, together with sweat chloride assay and PCR of mutations on exons 3, 4, 7, 9, 10, 11, 13, 14b, 17b, 19, 20 and 21 of the CFTR gene. RESULTS: None of the 8 patients with a renal anomaly presented a CFTR gene mutation, versus 23 out of 33 patients without a renal anomaly (p < 0.02). Seminal vesical anomalies were not more frequent in patients with or without mutations (11/20 versus 13/19, p = NS), except for composite heterozygous patients (with 2 mutations: 8/13 versus 4/11, p = NS). Spermatic parameters (pH < 7.2, fructose < 1 g/l and volume < 2 ml) could not distinguish between patients with or without renal or seminal vesical anomalies or mutation, except for patients with pH < 7.2, who presented fewer renal anomalies (2/25 versus 6/16, p < 0.05) and a higher incidence of gene mutation (19/25 versus 5/12, p < 0.01). CONCLUSION: Renal agenesis is considered to be pathognomonic of a developmental anomaly. Unlike a seminal vesical anomaly, a semen volume < 2 ml or fructose < 1 g/l, pH less than 7.2 is a nonspecific parameter, but more frequently present in patients with CFTR mutation.

Altered rep-1 expression due to substitution at position +3 of the IVS13 splice-donor site of the choroideremia (CHM) gene.

PURPOSE: To characterize the effect on mRNA splicing of a yet undescribed mutation located in intron 13 splice-donor sequence (IVS13 + 3A --> C) in the Rab-Escort-protein 1 gene of a patient with choroideremia. METHODS: The base substitution was firstly detected by the Single Strand conformation analysis from genomic DNA. A REP-1 cDNA region encompassing exons 10-14 was then specifically amplified from lymphocytes-derived mRNA. RESULTS: We could demonstrate that this substitution affects REP-1 RNA processing. The patient revealed only one aberrantly spliced mRNA lacking exon 13 and no normal transcript. CONCLUSION: The skipping of exon 13 results in the creation of a stop codon at the misspliced junction. This is the first case of nucleotide substitution at the +3 position of a splice donor site so far described in choroideremia.

Correlation between genito-urinary anomalies, semen analysis and CFTR genotype in patients with congenital bilateral absence of the vas deferens.

OBJECTIVE: To evaluate the incidence of renal and seminal vesicle (SV) abnormalities, and the presence or absence of CFTR gene mutations, in a cohort of patients referred for congenital bilateral absence of the vas deferens (CBAVD). PATIENTS AND METHOD: Forty-one patients with CBAVD, confirmed by surgical exploration, were evaluated by ultrasonography for renal and SV anomalies. Semen variables (pH, fructose level and ejaculate volume), sweat chloride levels and mutations of the 3, 4, 7, 9, 10, 11, 13, 14b, 17b, 19, 20 and 21 exons of the CFTR gene were determined. RESULT: In eight patients with renal anomalies there were no detectable mutations of CFTR, compared with 23 in the 33 patients with no renal anomalies (P < 0.02). SV anomalies were not related to the presence or absence of mutations (11 of 23 vs 11 of 18), or in compound heterozygote patients carrying two mutations (eight of 13 vs three of 10). Semen variables (pH < 7.2, fructose < 1 g/L and ejaculate volume < 2 mL) did not differentiate patients with or without anomalies of the kidney, SV or with mutations, except in patients with a pH < 7.2 for which renal anomalies were less frequent (two of 25 vs six of 16, P < 0.05) and mutations more frequent (19 of 25 vs five of 12, P < 0.01). CONCLUSION: Renal anomalies associated with CBAVD should be considered as supporting maldevelopment as a cause, but analysis of CFTR mutations in these cases should not be omitted. Unlike anomalies of the SV, a low ejaculate volume or low fructose level, a semen pH of < 7.2 is the only nonspecific variable in patients with CFTR mutations.

Length variations of the poly(T) tract at the exon 3 splice acceptor site of the choroideremia gene.

By using the single strand conformational analysis to search for point mutations in the choroideremia gene, we have identified an intronic polymorphism within the intron 2 of the CHM gene. We have studied the frequency of this polymorphism in the population from South of France.

Congenital bilateral absence of the vas deferens (CBAVD) and cystic fibrosis transmembrane regulator (CFTR): correlation between genotype and phenotype.

To assess better the link between congenital bilateral absence of the vas deferens (CBAVD) and cystic fibrosis (CF), we compared sweat chloride values, analysis of the CFTR intron 8 poly(T) tract length and analysis of 10 exons in a population of 38 patients with CBAVD. The data indicate that this population can be divided into three groups of patients. In the first group of 15 patients with abnormal sweat chloride (> 60 mmol/l), the frequency of CF mutations is high. In the second group of 18 patients with equivocal sweat chloride (between 40 and 60 mmol/l), the frequency of the 5T variant is high; 6 patients have a delta F508 mutation and a 5T variant and 1 patient is homozygous for the 5T variant; a 5T variant has been detected in 3 other patients, and a delta F508 mutation in another patient. A third group of 5 patients is probably not related to CF: these patients have other congenital abnormalities of the urogenital tract, low chloride values (< 40 mmol/l) and apparently no abnormality of the CF gene.

Genetic analysis of new French X-linked juvenile retinoschisis kindreds using microsatellite markers closely linked to the RS locus: further narrowing of the RS candidate region.

The gene involved in juvenile retinoschisis (RS) has previously been localized, by genetic linkage analyses, to Xp22.1-p22.2, between DXS274 and DXS43/DXS207; it is closely linked to the latter markers. From our recent data, this interval represents a genetic distance of approximately 10 cM. In the present study, we have studied 14 French families with X-linked juvenile RS by using four CA polymorphisms that are closely linked to the RS locus and that have recently been included in an Xp22.1-p22.2 high-resolution map. Complete cosegregation with the disease locus was observed for three of them, DXS207, DXS418, and DXS999, which further confirms the locus homogeneity for RS and the close linkage to this region. One recombinant was found with the most proximal marker, AFM291wf5, thereby defining this marker as the new proximal boundary of the candidate region for RS. Under the assumption that DXS207 and DXS43 constitute the distal boundary, the present study further reduces the region containing the disease gene to a interval of 3-4 cM. The results reported here should facilitate the eventual cloning of the RS gene.

Genotypes of cytochrome P450 and clinical response to clomipramine in patients with major depression.

The genetic cytochrome P450 polymorphism is reported in factors affecting the individual response to drugs. The interindividual variation at steady-state levels or also in elimination of drugs, finds an explanation in genetic differences in the metabolism. In particular, activities of the P450-IID6 isoenzyme are related to the sparteine/debrisoquine oxidation polymorphism. Phenotyping such a system has been proposed to analyse variability in the tricyclic antidepressant level. To analyse clinical relevance of a pharmacogenetic approach, we studied the cytochrome P450 CYP2D6 genotypes and the clinical responses to clomipramine in 21 hospitalised patients who met DSM-III-R criteria for major depression. Three patients were predicted as poor metabolizers. We suggested a limitation of clomipramine (CMI) hydroxylation in poor metaboliser (PM) patients which is balanced by a desmethylation. The clinical efficacy pattern does not differ in poor metaboliser and early metaboliser patients. Firstly, there is no significant differences in the evolution of scores on MADRS and specific retardation scale into the two groups. Secondly, outcome of side effects does not occur more frequently in PM patients. Clinical relevance of such an approach needs further study.