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Phenotype of ENAM mutations is dosage-dependent
D Ozdemir1, P S Hart, E Firatli
1Clinical Research Core, NIDCR/National Institutes of Health, 10 Center Drive, Building 10, Room 5-2531, Bethesda, MD 20892-1432, USA.
Journal of Dental Research
|October 26, 2005
Summary
Mutations in the ENAM gene cause enamel defects. This study found new ENAM mutations in Turkish families, showing that enamel pitting and hypoplastic amelogenesis imperfecta can be dose-dependent genetic traits.
Area of Science:
- Genetics
- Oral Biology
- Developmental Biology
Background:
- Amelogenesis imperfecta (AI) is a group of inherited dental disorders affecting tooth enamel formation.
- Mutations in the ENAM gene, encoding enamelin, are a known cause of hypoplastic AI.
- The spectrum of ENAM-related phenotypes, particularly the dose-dependency, requires further investigation.
Observation:
- This study investigated ENAM gene mutations in ten Turkish families with autosomal hypoplastic AI.
- ENAM mutations were identified in two families, revealing novel and previously described genetic alterations.
- Specific mutations correlated with distinct inheritance patterns and phenotypic severity.
Findings:
- A novel nonsense mutation (p.S246X) in ENAM caused dominant autosomal hypoplastic AI with localized enamel pitting.
- Compound heterozygosity for two insertion mutations in ENAM resulted in autosomal-recessive generalized hypoplastic AI.
- Heterozygous carriers of insertion mutations exhibited a localized enamel-pitting phenotype, suggesting a dose-dependent effect.
Implications:
- These findings confirm ENAM mutations as a significant cause of hypoplastic AI across different populations.
- The study highlights the dose-dependent nature of ENAM mutations, explaining varied phenotypes from localized pitting to severe hypoplasia.
- Understanding genotype-phenotype correlations in ENAM mutations is crucial for genetic counseling and potential therapeutic strategies.