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Title: Locus heterogeneity for Waardenburg syndrome is predictive of clinical subtypes

Abstract

Waardenburg syndrome (WS) is a dominantly inherited and clinically variable syndrome of deafness, pigmentary changes, and distinctive facial features. Clinically, WS type I (WS1) is differentiated from WS type II (WS2) by the high frequency of dystopia canthorum in the family. In some families, WS is caused by mutations in the PAX3 gene on chromosome 2q. We have typed microsatellite markers within and flanking PAX3 in 41 WS1 kindreds and 26 WS2 kindreds in order to estimate the proportion of families with probable mutations in PAX3 and to study the relationship between phenotypic and genotypic heterogeneity. Evaluation of heterogeneity in location scores obtained by multilocus analysis indicated that WS is linked to PAX3 in 60% of all WS families and in 100% of WS1 families. None of the WS2 families were linked. In those families in which equivocal lod scores (between -2 and +1) were found, PAX3 mutations have been identified in 5 of the 15 WS1 families but in none of the 4 WS2 families. Although preliminary studies do not suggest any association between the phenotype and the molecular pathology in 20 families with known PAX3 mutations and in four patients with chromosomal abnormalities in the vicinity of PAX3,more » the presence of dystopia in multiple family members is a reliable indicator for identifying families likely to have a defect in PAX3. 59 refs., 3 figs., 5 tabs.« less

Authors:
;  [1];  [2]; ;  [3]; ;  [4];  [5];  [6]
  1. Boston Univ. School of Medicine, MA (United States)
  2. Galludet Univ., Washington, DC (United States)
  3. Michigan State Univ., East Lansing, MI (United States)
  4. National Institute on Deafness and Other Communication Disorders, Bethesda, MD (United States)
  5. Univ. of Cape Town (South Africa)
  6. and others
Publication Date:
OSTI Identifier:
35504
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Journal of Human Genetics; Journal Volume: 55; Journal Issue: 4; Other Information: PBD: Oct 1994
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; HUMAN CHROMOSOME 2; GENETIC MAPPING; CHROMOSOMAL ABERRATIONS; HUMAN POPULATIONS; SENSE ORGANS DISEASES; HEREDITARY DISEASES; GENE MUTATIONS; PHENOTYPE; GENOTYPE; STATISTICAL MODELS

Citation Formats

Farrer, L.A., Hoth, C., Arnos, K.S., Asher, J.H. Jr., Friedman, T.B., Grundfast, K.M., Lalwani, A.K., Greenberg, J., and Diehl, S.R. Locus heterogeneity for Waardenburg syndrome is predictive of clinical subtypes. United States: N. p., 1994. Web.
Farrer, L.A., Hoth, C., Arnos, K.S., Asher, J.H. Jr., Friedman, T.B., Grundfast, K.M., Lalwani, A.K., Greenberg, J., & Diehl, S.R. Locus heterogeneity for Waardenburg syndrome is predictive of clinical subtypes. United States.
Farrer, L.A., Hoth, C., Arnos, K.S., Asher, J.H. Jr., Friedman, T.B., Grundfast, K.M., Lalwani, A.K., Greenberg, J., and Diehl, S.R. 1994. "Locus heterogeneity for Waardenburg syndrome is predictive of clinical subtypes". United States. doi:.
@article{osti_35504,
title = {Locus heterogeneity for Waardenburg syndrome is predictive of clinical subtypes},
author = {Farrer, L.A. and Hoth, C. and Arnos, K.S. and Asher, J.H. Jr. and Friedman, T.B. and Grundfast, K.M. and Lalwani, A.K. and Greenberg, J. and Diehl, S.R.},
abstractNote = {Waardenburg syndrome (WS) is a dominantly inherited and clinically variable syndrome of deafness, pigmentary changes, and distinctive facial features. Clinically, WS type I (WS1) is differentiated from WS type II (WS2) by the high frequency of dystopia canthorum in the family. In some families, WS is caused by mutations in the PAX3 gene on chromosome 2q. We have typed microsatellite markers within and flanking PAX3 in 41 WS1 kindreds and 26 WS2 kindreds in order to estimate the proportion of families with probable mutations in PAX3 and to study the relationship between phenotypic and genotypic heterogeneity. Evaluation of heterogeneity in location scores obtained by multilocus analysis indicated that WS is linked to PAX3 in 60% of all WS families and in 100% of WS1 families. None of the WS2 families were linked. In those families in which equivocal lod scores (between -2 and +1) were found, PAX3 mutations have been identified in 5 of the 15 WS1 families but in none of the 4 WS2 families. Although preliminary studies do not suggest any association between the phenotype and the molecular pathology in 20 families with known PAX3 mutations and in four patients with chromosomal abnormalities in the vicinity of PAX3, the presence of dystopia in multiple family members is a reliable indicator for identifying families likely to have a defect in PAX3. 59 refs., 3 figs., 5 tabs.},
doi = {},
journal = {American Journal of Human Genetics},
number = 4,
volume = 55,
place = {United States},
year = 1994,
month =
}
  • We have studied a large Mennonite kindred in which 20 members were affected with Hirschburg disease (HSCR), 5 of whom had one or more manifestations of Waardenburg syndrome (WS) type II (WS2). Eleven additional relatives had signs of WS2 without HSCR. Since HSCR and WS2 each represent perturbations of neural crest migration/differentiation, this large pedigree with apparent cosegregation of HSCR and WS2 offered an opportunity to search for linkage between these loci, candidate genes, and random DNA markers, particularly in view of recent discoveries of genes for Waardenburg syndrome type I (WS1) and Hirschsprung disease (c-ret). We have examined themore » following possible linked markers in 69 relatives in this family: the c-ret gene (HSCR); the human PAX3 gene (HuP2) on chromosome 2q (WS1) and placental alkaline phosphatase (ALPP) on chromosome 2q (linked to WS1); argininosuccinate synthetase (ASS) on chromosome 9q, close to ABO blood groups which have shown weak linkage to WS; and the {beta}1 GABA receptor gene (GABARB1) on chromosome 4q13-11, close to c-kit, deletions of which cause piebaldism. Linkage between any of these loci and HSCR/WS in this kindred was excluded, demonstrating that there is at least one further locus for HSCR other than c-ret. 45 refs., 1 fig., 3 tabs.« less
  • Waardenburg syndrome (WS) is a dominantly inherited and clinically variable syndrome of deafness, pigmentary changes and distinctive facial features. WS type I (WS1) is characterized by a high frequency of dystopia canthorum whereas WS type II (WS2) individuals have normal inter canthal distances. Previous studies have shown that WS1 is caused by mutations in the PAX3 gene on chromosome 2q whereas WS2 is unlinked to PAX3. However, analyses of WS2 families have been complicated by the possibility of misdiagnosis of secondary cases with mild features of WS2. We initiated a genome search in 8 WS2 families. Suggestive evidence for linkagemore » to D1S248 and AMY2B was found in one family (both markers: Z-max=2.4 at {Theta}=0), to D1S485 and D1S495 in a second family (both markers: Z-max=2.2 at {Theta}=0), and to D1S248 in a third family (Z-max=1.1 at {Theta}=.11). WS2 was not linked to any of these markers in the total group of families. Location scores for each family were calculated by a six-locus analysis using the marker map AMY2B/D1S486 - .03 - D1S495 - .02 - D1S248 - .05 - D1S457 - .04 - D1S250. Assessment of these scores for linkage and heterogeneity using the admixture test revealed significant evidence for linkage (P<.0001) under the assumption of heterogeneity ({alpha}=.40). The most likely location for WS2 is at D1S495, although either of the intervals flanking this marker may contain the mutant gene. All other locations were ruled out with odds of greater than l00 to 1. Our findings suggest that there are at least two loci for WS type II. Complementary crossovers in the linked families make feasible attempts to narrow the location of the WS2 gene by positional cloning. Analyses of additional families will be needed to estimate more precisely the proportion of linked families and identify the gene.« less
  • Waardenburg syndrome is an autosomal dominant disorder characterized by deafness and pigmentary abnormalities such as heterochromia of irides, hypopigmented skin patches, white forlock and premature graying. Clinically the syndrome has been classified into three types. Type II differs from type I in that dystopia canthorum is generally absent, and type III has associated limb anomalies. Recently linkage analysis localized the gene for WSI to chromosome 2q. PAX-3, which is a human analogue of the murine pax-3 locus, maps to this region and mutations in this gene have been found to segregate with WSI. However genetic heterogeneity clearly exists: most ifmore » not all WSII families are unlinked to PAX-3 while most if not all WSI cases are linked. We ascertained a four-year-old female child with an interstitial deletion of chromosome 13 who had features of WS including bilateral congenital sensorineural hearing loss, pale blue irides and pinched nostrils as well as hypertelorism microcephaly, bilateral eyelid ptosis, digitalization of thumbs and fifth finger clinodactyly. High resolution chromosomal analysis revealed a de novo interstitial deletion of 13q22-33.2. There was no family history of WS or retardation. A similar deletion in the region of 13q21-32 has been described in a 13-year-old boy with features of WSII. These two cases strongly suggested that this chromosomal region may include a second locus for WS. We have identified eight families with clinical features of WS type I which have been excluded from linkage to the PAX-3 locus. We have typed these families for microsatellite markers spanning chromosome 13. Linkage between WSII and the chromosome 13 markers was excluded in these families. Hirschsprung disease has been associated with WS and it has recently been mapped to chromosome 10q11.2-q21.1. We are currently typing the 8 families for microsatellites in this region.« less
  • We used segregation analysis to investigate the genetic basis of variation in dystopia canthorum, one of the key diagnostic features of Waardenburg syndrome type 1 (WS1). We sought to determine whether the W-index, a quantitative measure of this craniofacial feature, is influenced primarily either by allelic variation in the PAX3 disease gene or other major loci, by polygenic background effects, or by all of these potential sources of genetic variation. We studied both WS1-affected individuals and their WS1-unaffected relatives. After adjustment of the W-index for WS1 disease status, segregation analyses by the regression approach indicated major-locus control of this variation,more » although residual parent-offspring and sib-sib correlations are consistent with additional (possibly polygenic) effects. Separate analyses of WS1-affected and WS1-unaffected individuals suggest that epistatic interactions between disease alleles at the PAX3 WS1 locus and a second major locus influence variation in dystopia canthorum. Our approach should be applicable for assessing the genetic architecture of variation associated with other genetic diseases. 23 refs., 1 fig., 6 tabs.« less
  • A total of 25 DNA markers located on the long arm of human chromosome 2 have been mapped by fluorescence in situ hybridization. This region includes the locus for Waardenburg syndrome, type I (WS1), recently found to result, at least in some cases, from mutations of the PAX3 gene. The authors have established that the chromosomal location of the PAX3 gene is within band 2q36. They also show that three markers in the distal 2q region, including the PAX3 gene, are deleted in a patient with phenotypic features of WS1 associated with a de novo deletion (2)(q35q36.2). The improved physicalmore » map of this region should facilitate linkage mapping and positional cloning of loci on distal 2q. 46 refs., 2 figs., 1 tab.« less