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Title: Hemizygosity at the elastin locus and clinical features of Williams syndrome

Abstract

Williams syndrome is a recognizable syndrome characterized by distinctive facial appearance, gregarious personality, mental retardation, congenital heart defect, particularly supravalvular aortic stenosis (SVAS), and joint limitation. SVAS is an autosomal vascular disorder and the elastin gene was disrupted in patients with SVAS. Ewat et al. reported that hemizygosity at the elastin locus was detected in four familial and five sporadic cases of Williams syndrome. However, three patients did not have SVAS. We reconfirmed hemizygosity at the elastin locus in five patients with typical clinical features of Williams syndrome. Hemizygosity was detected in four cases with SVAS. However, one patient with distinctive facial appearance and typical Williams syndrome personality had two alleles of the elastin gene, but he did not have the congenital heart anomaly. Williams syndrome is thought to be a contiguous gene disorder. Thus, our data suggest that the elastin gene is responsible for the vascular defect in patients with Williams syndrome, and flanking genes are responsible for characteristic facial appearance and personality.

Authors:
;  [1];  [2]
  1. Ehime Univ. School of Medicine (Japan)
  2. Ibaraki Perfectural Handicap Children`s Hopsital (Japan) [and others
Publication Date:
OSTI Identifier:
134762
Report Number(s):
CONF-941009-
Journal ID: AJHGAG; ISSN 0002-9297; TRN: 95:005313-1501
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Journal of Human Genetics; Journal Volume: 55; Journal Issue: Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; GENES; GENE MUTATIONS; PATIENTS; PHENOTYPE; CONGENITAL MALFORMATIONS; MENTAL DISORDERS; CARDIOVASCULAR DISEASES; HEREDITARY DISEASES; DETECTION; STATISTICS

Citation Formats

Morimoto, Y, Kuwano, A., and Kuwajima, K. Hemizygosity at the elastin locus and clinical features of Williams syndrome. United States: N. p., 1994. Web.
Morimoto, Y, Kuwano, A., & Kuwajima, K. Hemizygosity at the elastin locus and clinical features of Williams syndrome. United States.
Morimoto, Y, Kuwano, A., and Kuwajima, K. 1994. "Hemizygosity at the elastin locus and clinical features of Williams syndrome". United States. doi:.
@article{osti_134762,
title = {Hemizygosity at the elastin locus and clinical features of Williams syndrome},
author = {Morimoto, Y and Kuwano, A. and Kuwajima, K.},
abstractNote = {Williams syndrome is a recognizable syndrome characterized by distinctive facial appearance, gregarious personality, mental retardation, congenital heart defect, particularly supravalvular aortic stenosis (SVAS), and joint limitation. SVAS is an autosomal vascular disorder and the elastin gene was disrupted in patients with SVAS. Ewat et al. reported that hemizygosity at the elastin locus was detected in four familial and five sporadic cases of Williams syndrome. However, three patients did not have SVAS. We reconfirmed hemizygosity at the elastin locus in five patients with typical clinical features of Williams syndrome. Hemizygosity was detected in four cases with SVAS. However, one patient with distinctive facial appearance and typical Williams syndrome personality had two alleles of the elastin gene, but he did not have the congenital heart anomaly. Williams syndrome is thought to be a contiguous gene disorder. Thus, our data suggest that the elastin gene is responsible for the vascular defect in patients with Williams syndrome, and flanking genes are responsible for characteristic facial appearance and personality.},
doi = {},
journal = {American Journal of Human Genetics},
number = Suppl.3,
volume = 55,
place = {United States},
year = 1994,
month = 9
}
  • Williams syndrome (WS) is a predominantly sporadic developmental disorder characterized by dysmorphic facial features, infantile hypercalcemia, premature aging of skin, mental retardation and gregarious personality. Supravalvular aortic stenosis (SVAS) and other vascular diseases caused by the narrowing of large elastic arteries are present in almost 80% of cases. Recently, hemizygosity at the elastin locus has been shown in sporadic WS, suggesting that this disease is caused by deletions encompassing the elastin gene on chromosome 7q11.23. Taking advantage of a large series of sporadic WS (27 cases), we have explored the potential application of novel microsatellite DNA markers in the rapidmore » detection of hemizygosity in WS. We report here a highly informative marker at locus D7S1870, which detected failure of parental inheritance in almost 75% of cases of WS in our series. This marker can be regarded therefore as a reliable and useful diagnostic tool in suspected cases of WS as well as in complicated forms of supravalvular aortic stenosis. 10 refs., 2 figs.« less
  • The ring 15 syndrome is characterized by intrauterine growth retardation, mental retardation, postnatal growth failure, triangular facies, 5th finger clinodactyly, leg-length discrepancy, cafe-au-lait spots and cryptorchidism. The degree of short stature varies from mild to severe and is associated with normal growth hormone and IGF-1 levels, but a wide range of bone age delay. These children retain de novo rings with breakpoints in the short arm at 15p12-11 and in the long arm at 15q26, the region to which the insulin-like growth factor type 1 receptor (IGFIR) has been mapped. We investigated if the degree of growth failure correlates withmore » disruption loss of the IGF1R gene. Ring breakpoints for all patients were determined by typing of RFLP and microsatellite markers from distal 15q for patients and their parents. The order of the loci studied is cen-IVD-FES-D15S130-E15S107-D15S87-D15S86-D15S3. All breakpoints mapped distal to D15S100. Presence or absence of the IGF1R gene on the ring chromsomes of five patients was ascertained by in situ hybridization and gene dosage blots using probes for the more proximally located genes IVD and c-Fes as controls. Heterozygosity for one patient was also confirmed by typing of a polymorphism in the 3{prime} UTR of IGF1R. Two patients who retained the IGF1R were hemizygous at D15S87 while two lacking the IGF1R retained D15S107 indicating that the IGF1R maps between these two markers. Three of the patients with severe growth failure (more than 4 SDs below the mean) were hemizygous at the IGF1R locus while the patient with borderline short stature had two copies of the IGF1R; she was subsequently found to be growth hormone deficient and has demonstrated a response to therapy. Our finding of severe short stature correlating with loss of one copy of the IGF1R suggests a potential role for heterozygous IGF1R mutations in other cases of unexplained growth failure.« less
  • To investigate the frequency of deletions of the elastin gene in patients with Williams syndrome (WS), we screened 44 patients by both FISH and PCR amplification of a dinucleotide repeat polymorphism. FISH was performed using cosmids containing either the 5{prime} or the 3{prime} end of the elastin gene. PCR analysis was performed on the patients and their parents with a (CA){sub n} repeat polymorphism found in intron 17 of the elastin locus. Of the 44 patients screened, 91% were shown to be deleted by FISH. Using the DNA polymorphism, both maternally (39%) and paternally (61%) derived deletions were found. Fourmore » patients were not deleted for elastin but have clinical features of WS. Since deletions of elastin cannot account for several features found in WS, these patients will be valuable in further delineation of the critical region responsible for the WS phenotype. Although PCR can be useful for determining the parental origin of the deletion, our results demonstrate that FISH analysis of the elastin locus provides a more rapid and informative test to confirm a clinical diagnosis of WS. The presence of two copies of the elastin locus in a patient does not, however, rule out WS as a diagnosis. 25 refs., 3 figs., 1 tab.« less
  • Williams syndrome (WS) is generally characterized by mental deficiency, gregarious personality, dysmorphic facies, supravalvular aortic stenosis, and idiopathic infantile hypercalcemia. Patients with WS show allelic loss of elastin (ELN), exhibiting a submicroscopic deletion, at 7q11.23, detectable by FISH. Hemizygosity is likely the cause of vascular abnormalities in WS patients. A series of 235 patients was studied, and molecular cytogenetic deletions were seen in 96% of patients with classic WS. Patients included 195 solicited through the Williams Syndrome Association (WSA), plus 40 clinical cytogenetics cases referred by primary-care physicians. Photographs and medical records of most WSA subjects were reviewed, and patientsmore » were identified as {open_quotes}classic{open_quotes} (n = 114) or{open_quotes}uncertain{close_quotes} (n = 39). An additional 42 WSA patients were evaluated without clinical information. FISH was performed with biotinylated ELN cosmids on metaphase cells from immortalized lymphoblastoid lines from WSA patients and after high-resolution banding analysis on clinical referral patients. An alpha-satellite probe for chromosome 7 was included in hybridizations, as an internal control. Ninety-six percent of the patients with classic WS showed a deletion in one ELN allele; four of these did not show a deletion. Of the uncertain WS patients, only 3 of 39 showed a deletion. Of the 42 who were not classified phenotypically, because of lack of clinical information, 25 patients (60%) showed a deletion. Thirty-eight percent (15/40) of clinical cytogenetics cases showed an ELN deletion and no cytogenetic deletion by banded analysis. These results support the usefulness of FISH for the detection of elastin deletions as an initial diagnostic assay for WS. 14 refs., 2 figs., 4 tabs.« less
  • To investigate deletions in the elastin gene in patients with Williams Syndrome (WS), we screened 37 patients and their parents for deletions in the elastin gene by both fluorescence in situ hybridization (FISH) using cosmid cELN272 containing the 5{prime} end of the elastin gene and by polymerase chain reaction (PCR) using a primer pair which amplifies intron 17 in the elastin gene, producing a polymorphic amplification product. Thirty-two patients have been investigated by both the FISH and PCR techniques, one patient was studied only by PCR, and 4 patients were studied only by FISH. Overall, 34 of 37 patients (92%)more » were deleted for the elastin gene. Using the PCR marker, 14 patients were informative and 12 were shown to be deleted [maternal (n=5) and paternal (n=7)]. Using cosmid cELN272, 33 of 36 patients demonstrated a deletion of chromosome 7q11.23. In one family, both the mother and daughter were deleted due to an apparently de novo deletion arising in the mother. Three patients were not deleted using the elastin cosmid; 2 of these patients have classic WS. Another non-deleted patient has the typical facial features and hypercalcemia but normal intelligence. These three patients will be important in delineating the critical region(s) responsible for the facial features, hypercalcemia, mental retardation and supravalvular aortic stenosis (SVAS). There was not an absolute correlation between deletions in elastin and SVAS, although these individuals may be at risk for other cardiovascular complications such as hypertention. Since the majority of WS patients are deleted for a portion of the elastin gene, most likely this marker will be an important diagnostic tool, although more patients will need to be studied. Those patients who are not deleted but clinically have WS will be missed using only this one marker. Expansion of the critical region to other loci and identification of additional markers will be essential for identifying all patients with WS.« less