Inherited distal myopathies represent a heterogeneous group of skeletal muscle disorders. One type of adult-onset, progressive autosomal dominant distal myopathy, frequently associated with dysphagia and dysphonia, has been mapped to chromosome 5q31 in a North American pedigree (vocal cord and pharyngeal weakness with distal myopathy; VCPDM). We recently identified a second large VCPDM family of Bulgarian descent and performed fine mapping of the critical interval. Sequencing of positional candidate genes revealed precisely the same non-conservative S85C missense mutation affecting an interspecies conserved residue in the MATR3 gene in both families (Senderek et al., Am J Human Genet, in press). MATR3 is expressed in skeletal muscle and encodes matrin 3, a component of the proteinaceous network that extends throughout the nucleus and has been termed the nuclear matrix. Different disease related haplotype signatures in the two families provide evidence that two independent mutational events at the same position in MATR3 cause VCPDM. Histopathological and electron microscopical analysis of two muscle biopsies revealed reduced matrin 3 immunoreactivity of muscle fiber nuclei and myonuclear degeneration as well as autophagic vacuoles in affected muscle fibers.

Myotilin (MYOT) is a promising candidate gene for Vocal Cord and Pharyngeal Weakness with Distal Myopathy (VCPDM, also known as MPD2). Located within the minimum VCPDM candidate interval, myotilin mutations also cause a similarly progressive and adult-onset muscle disease. We examined myotilin in VCPDM patients by sequence analysis, RT-PCR, Southern blotting, and western blotting. We detected no defects in the myotilin gene, transcript, or protein in VCPDM. We also report several useful SNPs and STRs for the analysis of myotilin in muscle diseases of suspected, yet unknown genetic origin. We conclude that MYOT mutations likely are not a cause of VCPDM.

Susceptibility genes for Alzheimer's disease are proving to be highly challenging to detect and verify. Population heterogeneity may be a significant confounding factor contributing to this difficulty. To increase the power for disease susceptibility gene detection, we conducted a genome-wide genetic linkage screen using individuals from the relatively isolated, genetically homogeneous, Amish population. Our genome linkage analysis used a 407-microsatellite-marker map (average density 7 cM) to search for autosomal genes linked to dementia in five Amish families from four Midwestern U.S. counties. Our highest two-point lod score (3.01) was observed at marker D4S1548 on chromosome 4q31. Five other regions (10q22, 3q28, 11p13, 4q28, 19p13) also demonstrated suggestive linkage with markers having two-point lod scores >2.0. While two of these regions are novel (4q31 and 11p13), the other regions lie close to regions identified in previous genome scans in other populations. Our results identify regions of the genome that may harbor genes involved in a subset of dementia patients, in particular the North American Amish community.

Apolipoprotein E (APOE) is the only universally confirmed susceptibility gene for late-onset Alzheimer disease (LOAD), although many loci are believed to modulate LOAD risk. The genetic homogeneity of isolated populations, such as the Amish, potentially provide increased power to identify LOAD susceptibility genes. Population homogeneity in these special populations may reduce the total number of susceptibility genes contributing to the complex disorder, thereby increasing the ability to identify any one susceptibility gene. Dementia in the Amish is clinically indistinguishable from LOAD in the general population. Previous studies in the Amish demonstrated a significantly decreased frequency of the APOE-4 susceptibility allele, but significant familial clustering of dementia [M.A. Pericak-Vance, C.C. Johnson, J.B. Rimmler, A.M. Saunders, L.C. Robinson, E.G. D'Hondt, C.E. Jackson, J.L. Haines, Alzheimer's disease and apolipoprotein E-4 allele in an Amish population, Ann. Neurol. 39 (1996) 700–704]. These data suggested that a genetic etiology independent of APOE may underlie the dementia observed in this population. In the present analysis, we focused on a large, multiplex, inbred Amish family (24 sampled individuals; 10 of whom are affected). We completed a genomic screen to identify novel LOAD loci (n = 316 genetic markers), using both model-dependent "affecteds-only" analysis (dominant and recessive) and model-independent affected relative pair analysis. Interesting results (lod > 1.5 or p < 0.01) were obtained for markers on eight chromosomes (2q, 5q, 6q, 7p, 8p, 8q, 11p, 18p, 18q, and 19q). The highest overall score was a multipoint lod score of 3.1 on chromosome 11p. Most regions we identified were not previously detected by genomic screens of outbred populations and may represent population-specific susceptibilities to LOAD. These loci are currently under further investigation in a study of LOAD including additional Amish families.

Purpose: To identify germ line CDH1 mutations in hereditary diffuse gastric cancer (HDGC) families and develop guidelines for management of at risk individuals.Experimental Design: We ascertained 31 HDGC previously unreported families, including 10 isolated early-onset diffuse gastric cancer (DGC) cases. Screening for CDH1 germ line mutations was done by denaturing high - performance liquid chromatography and automated DNA sequencing.Results: We identified eight inactivating and one missense CDH1 germ line mutation. The missense mutation conferred in vitro loss of protein function. Two families had the previously described 1003C>T nonsense mutation. Haplotype analysis revealed this to be a recurrent and not a founder mutation. Thirty-six percent (5 of 14) of the families with a documented DGC diagnosed before the age of 50 and other cases of gastric cancer carried CDH1 germ line mutations. Two of 10 isolated cases of DGC in individuals ages <35 years harbored CDH1 germ line mutations. One mutation positive family was ascertained through a family history of lobular breast cancer (LBC) and another through an individual with both DGC and LBC. Occult DGC was identified in five of six prophylactic gastrectomies done on asymptomatic, endoscopically negative 1003C>T mutation carriers.Conclusions: In addition to families with a strong history of early-onset DGC, CDH1 mutation screening should be offered to isolated cases of DGC in individuals ages (35 years and for families with multiple cases of LBC, with any history of DGC or unspecified GI malignancies. Prophylactic gastrectomy is potentially a lifesaving procedure and clinical breast screening is recommended for asymptomatic mutation carriers.

We have identified C7orf11, which localizes to the nucleus and is expressed in fetal hair follicles, as the first disease gene for nonphotosensitive trichothiodystrophy (TTD). C7orf11 maps to chromosome 7p14, and the disease locus has been designated "TTDN1" (TTD nonphotosensitive 1). Mutations were found in patients with Amish brittle-hair syndrome and in other nonphotosensititive TTD cases with mental retardation and decreased fertility but not in patients with Sabinas syndrome or Pollitt syndrome. Therefore, genetic heterogeneity in nonphotosensitive TTD is a feature similar to that observed in photosensitive TTD, which is caused by mutations in transcription factor II H (TFIIH) subunit genes. Comparative immunofluorescence analysis, however, suggests that C7orf11 does not influence TFIIH directly. Given the absence of cutaneous photosensitivity in the patients with C7orf11 mutations, together with the protein's nuclear localization, C7orf11 may be involved in transcription but not DNA repair.

Background: Mutations in the E-cadherin (CDH1) gene are a well documented cause of hereditary diffuse gastric cancer (HDGC). Development of evidence based guidelines for CDH1 screening for HDGC have been complicated by its rarity, variable penetrance, and lack of founder mutations.Methods: Forty three new gastric cancer (GC) families were ascertained from multiple sources. In 42 of these families at least one gastric cancer was pathologically confirmed to be a diffuse gastric cancer (DGC); the other family had intestinal type gastric cancers. Screening of the entire coding region of the CDH1 gene and all intron/exon boundaries was performed by bi-directional sequencing.Results: Novel mutations were found in 13 of the 42 DGC families (31% overall). Twelve of these mutations occur among the 25 families with multiple cases of gastric cancer and with pathologic confirmation of diffuse gastric cancer phenotype in at least one individual under the age of 50 years. The mutations found include small insertions and deletions, splice site mutations, and three non-conservative amino acid substitutions (A298T, W409R, and R732Q). All three missense mutations conferred loss of E-cadherin function in in vitro assays. Multiple cases of breast cancers including pathologically confirmed lobular breast cancers were observed both in mutation positive and negative families.Conclusion: Germline truncating CDH1 mutations are found in 48% of families with multiple cases of gastric cancer and at least one documented case of DGC in an individual under 50 years of age. We recommend that these criteria be used for selecting families for CDH1 mutational analysis.

The International Gastric Cancer Linkage Consortium (IGCLC) predicted that up to 25% of families fulfilling the criteria for hereditary diffuse gastric cancer (HDGC) would harbor CDH1 germline mutations. This was based on observations from the low number of diffuse gastric cancer families described at the time, and its validation would require analysis of larger numbers. Here we report the results of germline CDH1 mutation screening in 39 kindred with familial aggregation of gastric cancer, a subset of which fulfills the criteria defined by the IGCLC for HDGC. CDH1 germline mutations were detected in four of 11 (36.4%) HDGC families. No mutations were identified in 63.6% of HDGC families or in kindred with familial aggregation of gastric cancer not fulfilling criteria for HDGC. These results add support to the evidence that only HDGC families harbor germline mutations in CDH1 and that genes other than CDH1 remain to be identified.

To the Editor: We reported previously that the locus for hyperparathyroidism–jaw tumor syndrome (MIM 145001), HRPT2, appeared to be within a 0.7-cM region on chromosome 1q, on the basis of shared haplotype data from two families (Hobbs et al. Hobbs et al., 1999Hobbs MR Pole AR Pidwirny G Rosen IB Zarbo R Coon H Heath III, H Leppert M Jackson CE Hyperparathyroidism-jaw tumor syndrome: the HRPT2 locus is within a 0.7-cM region on chromosome 1q.Am J Hum Genet. 1999; 64: 518-525Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar). The map order of the markers was originally derived from the chromosome 1 maps from Généthon (Dib et al. Dib et al., 1996Dib C Faure S Fizames C Samson D Drouot N Vignal A Millasseau P Marc S Hazan J Seboun E Lathrop M Gyapay G Morissette J Weissenbach J A comprehensive genetic map of the human genome based on 5,264 microsatellites.Nature. 1996; 380: 152-154Crossref PubMed Scopus (2668) Google Scholar; Généthon Web site) and the Whitehead Institute for Genome Research (Whitehead Institute for Genome Research Web site). Recent work by Carpten et al. (Carpten et al., 2000Carpten JD Makalowska I Robbins CM Scott N Sood R Connors TD Bonner TI Smith JR Faruque MU Stephan DA Pinkett H Morgenbesser SD Su K Graham C Gregory SG Williams H McDonald L Baxevanis AD Klingler KW Landes GM Trent JM A 6-Mb high-resolution physical and transcription map encompassing the hereditary prostate cancer 1 (HPC1) region.Genomics. 2000; 64: 1-14Crossref PubMed Scopus (30) Google Scholar) and the human genome sequencing project (Lander et al. Lander et al., 2001Lander ES Linton LM Birren B Nusbaum C Zody MC Baldwin J Devon K et al.Initial sequencing and analysis of the human genome.Nature. 2001; 409: 860-921Crossref PubMed Scopus (16486) Google Scholar) have shed new light on the proposed locus. These detailed physical-map data change the order of two markers (underlined) that are important in defining the shared haplotype region (in parentheses), from (D1S466, D1S2701, CHLC.12F10, D1S240, D1S2848, D1S254), D1S191, D1S444 to (D1S466, D1S2701, CHLC.12F10, D1S240, D1S254), D1S444, D1S191, D1S2848 (centromeric to telomeric). This removes D1S2848 from the reported shared haplotype region. Telomeric to D1S240, a new marker also became available: 277P67-2A8 (GenBank accession number AF181675). This marker was not shared between the two families in question, further reducing the shared haplotype region to the area defined between D1S466 and D1S240 (∼1.8 cM): (D1S466, D1S2701, CHLC.12F10, D1S240), 277P67-2A8, D1S254, D1S444, D1S191, D1S2848. For the markers remaining in the shared haplotype region—D1S466, D1S2701, CHLC.12F10, and D1S240—the frequencies for the alleles found in the affected haplotype are 0.06, 0.74, 0.18, and 0.50, respectively. This gives a calculated frequency in the general population of 0.004, or 1/250. This haplotype is much more common than that calculated for the original proposed shared haplotype region (population frequency of 1/38,000) and indicates that the newly reduced shared haplotype region is not indicative of an HRPT2 haplotype. Furthermore, the reduced shared haplotype region (D1S466 to D1S240) now no longer overlaps with the nonrecombinant region for our families (277P67-2A8 to D1S306, or D1S477 in current databases [Human Genome Working Draft Web site]). We conclude that the HRPT2 gene must lie within this 14.7-cM nonrecombinant region. Although our initial shared haplotype data provided misleading results, the examination of shared haplotype data in different families has proven valuable in refining the map location for other disease gene loci (i.e., the loci for autosomal dominant Stargardt-like macular dystrophy [Donoso et al. Donoso et al., 2001Donoso LA Frost AT Stone EM Weleber RG MacDonald IM Hageman GS Cibis GW Ritter III, R Edwards AO Autosomal dominant Stargardt-like macular dystrophy: founder effect and reassessment of genetic heterogeneity.Arch Ophthalmol. 2001; 119: 564-570Crossref PubMed Scopus (26) Google Scholar] and primary erythermalgia [Drenth et al. Drenth et al., 2001Drenth JP Finley WH Breedveld GJ Testers L Michiels JJ Guillet G Taieb A Kirby RL Heutink P The primary erythermalgia-susceptibility gene is located on chromosome 2q31-32.Am J Hum Genet. 2001; 68: 1277-1282Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar]) and should continue to be explored in uncommon genetic diseases. This work was supported, in part, by National Institutes of Health grant DK-38855, American Cancer Society Institutional Research Grant IRG-178F, American Cancer Society Institutional Research Grant IRG-178G (to the Huntsman Cancer Institute), a Shannon Award from the National Institutes of Health (grant 1 R55 CA75177-01), National Center for Research Resources grant M01-RR00064 (to the University of Utah School of Medicine General Clinical Research Center), and the Dykstra Foundation, Detroit. We gratefully acknowledge Drs. John D. Carpten and Jeffery M. Trent for providing mapping data and marker sequences for these studies. We also gratefully acknowledge the many physicians and dentists who supplied information on the study kindreds. We are particularly grateful to the family members who have patiently supplied information and samples for these studies.

MEN1 is an autosomal dominant disorder characterized by parathyroid, pituitary, and pancreatic tumors. The MEN1 gene is located on chromosome 11q13 and encodes a 610-amino acid protein. MEN1 mutations are of diverse types and are scattered throughout the coding region, such that almost every MEN1 family will have its individual mutation. To further characterize such mutations we ascertained 34 unrelated MEN1 probands and undertook DNA sequence analysis. This identified 17 different mutations in 24 probands (2 nonsense, 2 missense, 2 in-frame deletions, 5 frameshift deletions, 1 frameshift deletional-insertion, 3 frameshift insertions, 1 donor splice site mutation, and a g-->a transition that resulted in a novel acceptor splice site in intron 4). The intron 4 mutation was found in 7 unrelated families, and the tumors in these families varied considerably, indicating a lack of genotype-phenotype correlation. However, this intron 4 mutation is the most frequently occurring germline MEN1 mutation ( approximately 10% of all mutations), and together with 5 others at codons 83-84, 118-119, 209-211, 418, and 516, accounts for 36.6% of all mutations, a finding that indicates an approach for identifying the widely diverse MEN1 mutations.

Cationic trypsinogen and cystic fibrosis mutations have been identified in pancreatitis patients, although no study has looked for mutations in both genes in the same patient. Pancreatitis can be induced by alcohol, although not all alcoholics develop pancreatitis. We hypothesize that this phenomenon is due to a genetic predisposition in persons with alcohol-related pancreatitis. We performed sequence analysis of the cationic trypsinogen-coding region in 46 alcohol-related pancreatitis patients and 16 patients with pancreatitis due to causes other than alcohol. We also screened for 40 cystic fibrosis mutations including the 5T allele. No cationic trypsinogen mutations were identified. Cystic fibrosis mutation screening identified the DeltaF508 mutation in two Caucasian alcoholic patients (P<0.025). The cystic fibrosis mutation carrier frequency in African-American alcoholic patients was 3%, which was not significantly increased compared with the normal carrier frequency. The frequency of the 5T allele was not significantly increased compared with the normal population carrier frequency in either racial group. These results may suggest a role for the cystic fibrosis gene in alcohol-related pancreatitis but indicate that cationic trypsinogen mutations are not a common predisposing risk factor for alcohol-related pancreatitis. A multicenter study is necessary to attain sufficient numbers to come to a conclusion.

Microsatellite instability (MSI) is observed in 13-44% of gastric carcinoma. The etiology of MSI in gastric carcinoma has not been clearly defined. To assess the role of mismatch repair in the development of MSI in gastric cancer, expression of hMSH2 and hMLH1 was explored. We examined 117 gastric carcinomas for MSI and observed instability at one or more loci in 19 (16%) of these tumors. Of the 19 tumors with MSI, nine exhibited low-rate MSI (MSI-L) with instability at <17% of loci, whereas the remaining 10 exhibited high-rate MSI (MSI-H) with instability at >33% of loci examined. Immunohistochemical staining for hMLH1 and hMSH2 was performed on eight of the tumors with MSI-H, five with MSI-L, and 15 tumors without MSI. All eight tumors with MSI-H showed loss of staining for either hMLH1 (n = 5) or hMSH2 (n = 3). In contrast, tumors with MSI-L or without MSI all showed normal hMSH2 and hMLH1 protein expression patterns. Moreover, all eight of the tumors with MSI-H also showed instability at BAT-26, whereas none of the MSI-L tumors or tumors without instability showed instability at BAT-26. These findings suggest that the majority of high-level MSI in gastric cancer is associated with defects of the mismatch repair pathway. Although larger studies are needed, BAT-26 appears to be a sensitive and specific marker for the MSI-H phenotype in gastric carcinoma.

Families with autosomal dominant inherited predisposition to gastric cancer have been described. More recently, germline E-cadherin/CDH1 mutations have been identified in hereditary diffuse gastric cancer kindred. The need to have protocols to manage and counsel these families in the clinic led a group of geneticists, gastro enterologists, surgeons, oncologists, pathologists, and molecular biologists to convene a workshop to produce consensus statements and guidelines for familial gastric cancer. Review of the available cancer pathology from people belonging to families with documented germline E-cadherin/CDH1 mutations confirmed that the gastric cancers were all of the diffuse type. Criteria to define the different types of familial gastric cancer syndromes were agreed. Foremost among these criteria was that review of histopathology should be part of the evaluation of any family with aggregation of gastric cancer cases. Guidelines for genetic testing and counselling in hereditary diffuse gastric cancer were produced. Finally, a proposed strategy for clinical management in families with high penetrance autosomal dominant predisposition to gastric cancer was defined.

The autosomal progressive muscular dystrophies which are grouped together under the term limb girdle muscular dystrophies (LGMD) are diseases characterized by a progressive impairment of the proximal limb muscles and myopathic changes on electromyogram and muscle biopsy. Eight independent purely recessive genetic entities have been recognized in this group of diseases by genetic localization or causative gene identification. We have developed fluorescent genetic markers bracketing six of these loci (LGMD2A–LGMD2F). The marker loci were genotyped in 96 LGMD2 families leading to genetic definition of 25 of them either with a high likelihood or with a suggested localization (7 LGMD2A, 5 LGMD2B, 4 LGMD2C, 4 LGMD2D, 2 LGMD2E and 3 LGMD2F). In addition, 18 families were excluded for all six tested loci; for 45 of the 53 remaining families at least one exclusion could be demonstrated. This kit, which makes the rapid genetic testing of LGMD2 families possible, may be useful in a diagnostic process.

Hereditary Hemorrhagic Telangiectasia (HHT) is an autosomal dominant disorder characterized by multisystemic vascular dysplasia and recurrent hemorrhage from the sites of vascular lesions. Two genes have been identified for HHT. Endoglin, a TGF-beta binding protein which maps to chromosome 9q3, is the gene for HHT1. The type and location of most of the previously described mutations in the endoglin (ENG) gene suggested a dominant-negative model of receptor-complex dysfunction for the molecular basis of this disorder. In this article we describe 11 novel ENG mutations in HHT kindreds, which include missense and splice-site mutations. Two identical missense mutations in unrelated families disrupt the start codon of the gene. In addition, some frameshift and nonsense mutations lead to very low or undetectable levels of transcript from the mutant allele. These combined data suggest that the nature of most ENG mutations is to create a null (nonfunctional) allele, and that there is no requirement for the synthesis of a truncated endoglin protein in the pathogenesis of HHT.

E-cadherin germ-line mutations have recently been described as a molecular basis for early-onset familial gastric cancer in Maori kindred. We screened 18 gastric cancer families of European origin for germ-line mutations to determine the proportion in which E-cadherin mutations occur and the clinical characteristics of the affected families. Truncating mutations were identified in three kindred with familial diffuse gastric cancer. In these families, the age of onset of gastric cancer was variable, the penetrance was incomplete, and one kindred contained individuals with cancers at other sites. Here, we show that a proportion of diffuse gastric cancer families of European origin have germ-line E-cadherin mutations; however, these mutations are absent in intestinal gastric cancer families.

Distal myopathy refers to a heterogeneous group of disorders in which the initial manifestations are weakness and atrophy of the hands and feet. We report a family segregating an autosomal dominant distal myopathy, with multiple affected individuals in whom vocal cord and pharyngeal weakness may accompany the distal myopathy, without involvement of the ocular muscles. To our knowledge, this pedigree displays a distinct distal myopathy with the added features of pharyngeal and vocal cord dysfunction (VCPDM) that has not been previously reported. We mapped the MPD2 gene for VCPDM to chromosome 5q within a 12-cM linkage interval between markers D5S458 and D5S1972 in a large pedigree (a maximum LOD score of 12.94 at a recombination fraction of 0 for D5S393) and combined genome screening and DNA pooling successfully adapted to fluorescent markers. This technique provides for the possibility of fully automated genome scans.