Absence of linkage between familial neural tube defects and PAX3 gene.

Neural tube defects (NTD) are among the most common and disabling birth defects. The aetiology of NTD is unknown and their genetics are complex. The majority of NTD cases are sporadic, isolated, nonsyndromic, and generally considered to be multifactorial in origin. Recently, PAX3 (formerly HuP2, the human homologue of mouse Pax-3), on chromosome 2q35-37, was suggested as a candidate gene for NTD because mutations of Pax-3 cause the mouse mutant Splotch (Sp), an animal model for human NTD. Mutations in PAX3 were also identified in patients with Waardenburg syndrome type 1 (WS1). At least eight patients with both WS1 and NTD have been described suggesting pleiotropy or a contiguous gene syndrome. Seventeen US families and 14 Dutch families with more than one affected person with NTD were collected and 194 people (50 affected) from both data sets were genotyped using the PAX3 polymorphic marker. The data were analysed using affecteds only linkage analysis. The lod scores were -7.30 (US), -3.74 (Dutch), and -11.04 (combined) at theta = 0.0, under the assumption of the autosomal dominant model. For the recessive model, the lod scores were -3.30 (US), -1.46 (Dutch), and -4.76 (combined) at theta = 0.0. Linkage between PAX3 and familial NTD was excluded to 9.9 cM on either side of the gene for the dominant model and to 3.63 cM on either side of the gene for the recessive model in the families studied. No evidence of heterogeneity was detected using the HOMOG program. Our data indicate that PAX3 is not a major gene for NTD.     

Three novel PAX6 mutations in patients with aniridia.

AIMS: To describe mutations in the PAX6 gene in five patients with aniridia from three unrelated families. METHODS: The PAX6 gene was analysed using single stranded conformational polymorphism analysis and direct sequencing. RESULTS: In one family, three individuals from two generations had aniridia, whereas in each of the other families only one member was affected. The first patient had the heterozygous Q221X (1023C --> T) nonsense mutation in exon 8. The same mutation was found in his mother and sister. Another patient had a heterozygous Q297X (1252C --> T) mutation in exon 10. The third patient carried a heterozygous IVS5+2T --> C mutation leading to aberrant splicing of mRNA. CONCLUSIONS: These findings provide further examples of haploinsufficiency of PAX6 in aniridia.     

先天性多数牙齿缺失家系 PAX9基因两个新突变功能的初步研究

目的 对成对盒基因（paired box gene，PAX）PAX9两个新突变109（InsG）及139（C→T）分子生物学功能及与先天性多数牙齿缺失的发病机理进行初步探讨。方法分别以先天性多数牙齿缺失家系A[109（InsG）]、家系B[139（C→T）]中患者及健康成员基因组DNA为模板，PCR扩增PAX9基因DNA结合域序列（paired domain，PD），构建原核表达质粒GST，进一步在大肠杆菌中诱导表达，纯化表达产物，分离制备PAX9PD蛋白。凝胶迁移试验检测PAX9PD蛋白与靶DNA（CD19-2和Pax6CON）结合活性。结果 野生型PAX9PD蛋白与靶DNA结合，109（InsG）及139（C→T）突变的PAX9PD蛋白皆失去与靶DNA结合能力。结论 109（InsG）及139（C→T）突变造成PAX9基因DNA结合域功能丧失，可能是导致多数牙齿先天性缺失的原因。     

BMPR2 mutations found in Japanese patients with familial and sporadic primary pulmonary hypertension

Primary pulmonary hypertension (PPH) is a potentially lethal disorder, in which heterozygous mutations within the bone morphogenetic protein type II receptor (BMPR2) gene (BMPR2) have been identified. We conducted a molecular study of BMPR2 mutations in 4 Japanese families with familial PPH and 30 Japanese patients with sporadic PPH, and found 13 different mutations, of which 10 were novel, including missense (n=2), nonsense (n=4), frameshift (n=3), and splice-donor site (n=1) mutations. In total, BMPR2 mutations were found in all 4 familial PPH cases and 12 (40%) of the sporadic PPH cases. Further, a majority of the mutations found were predicted to cause premature termination, as previously reported. In the 9 mutations found in the sporadic cases, 2 were shown to be de novo, 2 were shared in multiple cases, 1 was shared with an FPPH case, and 1 was the same as previously reported in Caucasian FPPH. These results indicate that a substantial portion of Japanese PPH patients carry BMPR2 mutations with considerable heterogeneity.     

Three novel mutations of the PAX6 gene in Japanese aniridia patients

Mutations in the PAX6 gene of Japanese aniridia patients were analyzed. Four types of mutations including one known (474delC) and three novel (786_787ins10, 678_688del11 and 572_575delAATCins14) were found in six patients from four families. A patient with the mutation 572_575delAATCins14 also manifested VATER association. This is the first case of aniridia accompanied by VATER association. All of mutations found in this study are frameshift type, resulting in premature termination of translation. The database for PAX6 gene mutation has been made using a graphical data display system MutationView (). Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Risks of vesicoureteric reflux in the transplanted kidney.

The risk to the transplanted kidney of vesicoureteric reflux was evaluated in 150 consecutive first cadaveric renal allografts surviving for over three months. Of the 119 (79 per cent) allografts studied by micturating cystography 29 (24 per cent) were shown to reflux. The presence of reflux was associated with urine leakage and reoperation, and with ureteric insertion involving a short intramural tunnel. Graft failure (graft nephrectomy or death from renal failure) occurred in 14 of 29 refluxing grafts as compared to 14 failures in 90 nonrefluxing grafts (P less than 0.01). Graft failure in the refluxing group was typically slow, and commonly associated with proteinuria, microscopic hematuria, hypertension and a biopsy appearance of mesangiocapillary glomerular change. Urinary infection, though frequent (69 per cent), was not more common in the group with than in that without reflux. Vesicoureteric reflux is an important cause of late renal-graft failure.     

Erratum: BMPR2 mutations found in Japanese patients with familial and sporadic primary pulmonary hypertension

During the rendering of the .pdf version of this article, the °C units were replaced with question marks in Table 1. Please find the proper Table 1 published in the online version of this erratum.     

Genotype-phenotype correlations of new causative APC gene mutations in patients with familial adenomatous polyposis.

Nine new causative mutations and seven previously characterised mutations of the APC gene of patients with familial adenomatous polyposis (FAP) were analysed for any genotype-phenotype correlations. The only clear genotype-phenotype correlation found was between the position of the mutation site and the presence or absence of congenital hypertrophy of the retinal pigment epithelium (CHRPE). A more distal mutation site was associated with an earlier age of onset of symptoms and a larger number of colonic polyps, but a notable amount of intrafamilial variation was observed.     

Absence of exon 15 BRAF germline mutations in familial melanoma

We have analyzed DNA from peripheral blood of 42 cases of familial melanoma for germline mutations in exon 15 of the BRAF gene. No evidence of mutation was found. We have also analyzed DNA extracted from secondary melanoma from two members of these families. These results were also negative. In addition we have searched for exon 15 BRAF mutations in 24 samples of secondary melanoma from 22 cases of sporadic melanoma and detected the 1796T>A BRAF mutation which leads to a substitution of valine by glutamic acid at position 599 (V599E) in six samples. Peripheral blood DNA from two of these tumor-positive cases of sporadic melanoma were negative for the V599E BRAF mutation. This mutation therefore appears to be a somatic mutation associated with melanoma development and/or progression in a proportion of affected individuals.     

Germline mutations of E-cadherin gene in Korean familial gastric cancer patients

Gastric cancer is the most common cancer in Korea. Germline mutations of the E-cadherin gene have recently been identified in familial gastric cancer patients. We screened five Korean familial gastric cancer patients to investigate germline mutations of the E-cadherin gene. These patients fulfilled the following criteria: presence of at least two gastric cancer patients within first-degree relatives and one patient diagnosed before the age of 50 years. Abnormal band patterns were found in exons 6 and 10 in two familial gastric cancer patients by polymerase chain reaction-single strand conformation polymorphism analysis (probands from the SNU-G2 and SNU-G1001 families, respectively). DNA sequencing analysis of the E-cadherin gene of these two patients revealed missense mutations in each exon. The SNU-G2 proband harbored a missense mutation from aspartic acid (GAT) to glycine (GGT) at codon 244 in exon 6 of the E-cadherin gene, and the SNU-G1001 proband had a missense mutation from valine (GTG) to alanine (GCG) at codon 487 in exon 10. The SNU-G2 proband was diagnosed with gastric cancer at the age of 38; three brothers and two sisters had died of gastric cancer under the age of 50, and their mother had died of gastric cancer at the age of 63. The SNU-G1001 proband was diagnosed with gastric cancer at the age of 42 and one brother had died of gastric cancer at the age of 49. In summary, we found germline mutations of the E-cadherin gene in two of five Korean familial gastric cancer patients screened. Received: January 4, 1999 / Accepted: February 4, 1999     

Absence of mutations in the homeodomain of the MSX1 gene in patients with hypodontia

Hypodontia, the congenital absence of one or a few permanent teeth, is one of the most frequent alterations of the human dentition. Although hypodontia does not represent a public health problem, it may cause both speech and masticatory dysfunction and esthetic problems. A missense mutation in the homeodomain of MSX1 gene has been associated with hypodontia of second premolars and third molars in humans. However, another study excluded this gene as causative locus for hypodontia of incisors and premolars. To further investigate the role of the MSX1 gene in human hypodontia, we analyzed the homeobox region of the MSX1 gene in 20 individuals with different patterns of familial or isolated hypodontia. The direct sequencing of PCR products did not show any polymorphisms or mutations in the human MSX1 gene. Our results indicate that inactivation of MSX1 gene in humans must have a highly selective effect on dentition, and other genes must be involved in the cause of hypodontia in humans.     

Three novel small deletion mutations of the LDL receptor gene in Korean patients with familial hypercholesterolemia.

The low-density lipoprotein (LDL) receptor gene from 80 unrelated Korean patients with familial hypercholesterolemia (FH) was analyzed to screen for small structural rearrangements that could not be detected by Southern blot hybridization. Three different small deletions were detected in exon 11 of 3 FH patients and were characterized by DNA sequence analysis. Of them two mutations are in-frame 36-bp (FH 2) and 9-bp (FH 34) deletions that result in the loss of twelve amino acids (from Met510 to Ile521) and three amino acids (Thr513, Asp514 and Trp515), respectively. Both mutations are located in the third of the five YWTD motifs of the LDL receptor gene. The third mutation (FH 400) is a 2-bp deletion that shifts the translational reading frame and results in a prematurely terminated receptor protein. The generation of a 36-bp deletion can be explained by the formation of a hairpin-loop structure mediated by inverted repeat sequences. On the other hand, the mechanism responsible for the 9- and the 2-bp deletions is probably strand-slippage mispairing mediated by short direct repeats. All of these three deletions are novel mutations. Each of the three deletions was detected only in a single pedigree out of 80 FH families analyzed.     

Absence of COCH mutations in patients with Meniere disease

Missense mutations in the coagulation factor C homology (COCH) gene (14q12-q13) cause the autosomal dominant sensorineural hearing loss and vestibular disorder DFNA9 (OMIM 603196), and a high prevalence of symptoms of Meniere disease (MD) has been described in families with a mutation in the COCH gene. In this study, we search for mutations in the COCH gene in peripheral blood from patients with definite MD. DNA was extracted from peripheral blood cells of 30 individuals with MD and 30 controls. Exons 4 and 5 of the COCH gene were amplified by PCR reaction, using primer pairs flanking both exons. Sequences were analysed by a DNA sequencing system and compared with the published COCH cDNA sequence. No differences were found in the nucleotide sequences of exons 4 and 5 in the COCH gene in patients with definite sporadic MD when they were compared with the control group. Patients with definite MD have a low prevalence of mutations in exons 4 and 5 of the COCH gene.     

Three novel aniridia mutations in the human PAX6 gene

Aniridia (iris hypoplasia) is an autosomal dominant congenital disorder of the eye. Mutations in the human aniridia (PAX6) gene have now been identified in many patients from various ethnic groups. In the study reported here we describe PAX6 mutations in one sporadic and five familial cases with aniridia. Of the four different mutations identified, one was identical to a previously reported mutation (C→T transition at codon 240), and three were novel: two in the glycine-rich region and one in the proline/serine/threonine-rich (PST) region. One PAX6 mutation found in the PST region was associated with cataracts in an aniridia family. Another splice mutation in the PST domain occured in an aniridia patient with anosmia (inability to smell) The sixnew aniridia cases reported here have mutations predicted to generate incomplete PAX6 proteins. These results support the theory that human aniridia is caused by haploinsufficiency of PAX6. © 1995 Wiley-Liss, Inc.     

Somatic NF2 gene mutations in familial and non-familial vestibular schwannoma

Vestibular schwannoma occurs both as a sporadic tumour and Inthe dominantly inherited familial cancer syndrome neuroflbromatosistype 2 (NF2). The gene for NF2 has recently been Isolated onchromosome 22, and the demonstration of inactivating germllnemutations In NF2 patients and NF2 associated tumours suggeststhat it act as a tumour suppressor. We have investigated 85sporadic and 2 NF2 associated vestibular schwannomas, and onevagal schwannoma for chromosome 22 allele loss and NF2 genemutations. A further 7 vestibular schwannomas were Investigatedfor NF2 mutations only. Chromosome 22 allele loss was detectedin 34 of 87 vestibular schwannomas and In the vagal nerve schwannoma.Six exons of the NF2 gene were Investigated by SSCP analysisin all 95 tumours. Somatic NF2 gene mutations were detectedIn 13 non-familial vestibular schwannomas. and in one of theNF2 vestibular schwannomas. Seven non-famlllal tumours withan NF2 gene mutation also displayed a chromosome 22 allele loss.Thirteen of the mutations were predicted to produce truncationof the NF2 protein. These results suggest that somatic mutationsof the NF2 tumour suppressor gene are a critical step In thepathogenesis of both famlllal and non-famlllal vestibular schwannomaand that the mechanism of tumourigenesis complles with a ‘two-hit’mutation model.