Norrie disease pedigree carrying the novel mutation C65Y, predicted to disrupt the cystine knot growth factor motif, analyzed by RasI restriction digestion
- Univ. of Toronto, Ontario (Canada); and others
Norrie disease (MIM 310600; ND) is an X-linked (Xp11.2-11.3) neurodevelopmental disorder characterized by congenital blindness, retinal dysplasia with pseudoglioma formation, and often associated with progressive mental retardation and deafness. The ND gene, comprised of 3 exons, codes for an evolutionarily conserved protein of 133 amino acids. We have analyzed 8 pedigrees segregating Norrie disease. Although microdeletions have been detected in several typical ND patients, Southern blot analysis with probes L1.28, MAO-A, MAO-B, TIMP-3.9X, pTak8, and M27{beta} failed to detect such deletions in these 8 ND pedigrees. With the cloning of the ND gene, PCR analysis of all 3 exons likewise did not reveal any insertions or deletions. SSCP analysis ({sup 35}S-dNTP PCR) on PCR products of exon 3 showed a band shift for 1 patient. Repeat `cold` SSCP on minigels (3 inches x 4 inches) followed by liver staining was confirmatory. Direct sequencing revealed a G{r_arrow}A transition at nucleotide 610 corresponding to amino acid 65, changing Cys to Tyr. The mutation created an RsaI site, such that the uncut, normal, and mutant PCR products (using the same PCR primers) were 297 bp, 243 and 54 bp, and 177, 72 and 54 bp respectively. Affected males in the relevant pedigree had restricted PCR products of 177, 72 and 54 bp, carrier mothers 243, 177, 72, and 54 bp, and normals, including 30 unrelated individuals, 243 and 54 bp. Recent evidence indicates that the ND gene has a C-terminal domain homologous to that of TGF{beta}, thus identifying it as putative peptide growth factor, providing a monogenic disease model for the family of cystine knot growth factors. This is the first report of a mutation in Cys 2, critical for crosslinking to Cys 5 forming a disulphide bridge which holds the cystine knot growth factor tertiary structure together.
- OSTI ID:
- 134773
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-1512
- Journal Information:
- American Journal of Human Genetics, Vol. 55, 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
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BASIC STUDIES
GENES
GENE MUTATIONS
DNA-CLONING
DNA SEQUENCING
GENETIC MAPPING
DETECTION
PATIENTS
MENTAL DISORDERS
NERVOUS SYSTEM DISEASES
SENSE ORGANS DISEASES
PHENOTYPE
PROTEINS
GROWTH FACTORS
BIOLOGICAL MODELS
STRUCTURE-ACTIVITY RELATIONSHIPS
HUMAN X CHROMOSOME
GENETICS
AMINO ACIDS
EXONS
POLYMERASE CHAIN REACTION
NUCLEOTIDES
CYSTINE