Deletions and candidate genes in Williams syndrome

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:133429

Perez Jurado, L A; Peoples, R; Francke, U ^[1]

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1. Stanford Univ. CA (United States); and others

Hemizygosity at the elastin locus (ELN) on chromosome 7q11.23 has recently been reported in several familial and sporadic cases of the developmental disorder, Williams syndrome (WS). Because the deletion is greater than the span of the ELN gene, a contiguous gene deletion syndrome has been suggested as the probable molecular basis for this condition. Thus far, neither the size of the deletion(s), nor other genes within it are known. We have analyzed samples from 27 sporadic WS patients by genotyping two multiallelic ELN intragenic polymorphisms, detectable by PCR amplification, and by Southern blotting for ELN gene dosage. Twenty four patients were hemizygous at the ELN locus while 3 showed no deletion or detectable rearrangement. Genotype studies on parental DNA were informative in 12 of the deletions. All 12 were due to de novo events, 8 in the maternal and 4 in the paternal chromosome. In an attempt to identify genes involved in WS we are also using a candidate gene approach. Delayed clearance of an exogenous calcium load with normal or slightly increased calcitonin levels in serum has been documented in WS patients suggesting a defective calcitonin action or calcium sensing function. The calcitonin receptor (CTR) gene is, therefore, a good candidate since CTR has a dual role as a hormonal receptor for calcitonin and an extracellular calcium sensor. We have mapped the CTR gene to chromosome 7q21.1 by PCR-SSCA of somatic cell hybrids and FISH analysis. Using two color FISH with probes for ELN and CTR, both loci are located on 7q at a distance of {approximately}10 Mb, CTR being telomeric. Our CTR probe does not detect any genomic abnormality by FISH or Southern blot in the patients` samples analyzed. We have identified a diallelic polymorphism in the CTR cDNA and are currently testing the hypothesis of an impaired CTR expression as responsible for some of the clinical features of WS by analysing the CTR transcripts by RT-PCR.

• OSTI ID: 133429
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
CALCITONIN
CARDIOVASCULAR DISEASES
DNA HYBRIDIZATION
FLUORESCENCE
GENE MUTATIONS
GENES
GENETIC MAPPING
GENETICS
GENOTYPE
HEREDITARY DISEASES
HUMAN CHROMOSOME 17
MENTAL DISORDERS
METABOLISM
PATIENTS
POLYMERASE CHAIN REACTION
PROBES
RECEPTORS
SIZE
SOMATIC CELLS
TRANSCRIPTION