Amelogenesis Imperfecta News and Articles
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What is amelogenesis imperfecta?
Amelogenesis imperfecta is a disorder of tooth development. This condition causes teeth to be unusually small, discolored, pitted or grooved, and prone to rapid wear and breakage. Other dental abnormalities are also possible, and the defects vary among affected individuals. These problems can affect both primary (baby) teeth and permanent teeth.
Researchers have described at least 14 forms of amelogenesis imperfecta. These types are distinguished by their specific dental abnormalities and by their pattern of inheritance.
How common is amelogenesis imperfecta?
The exact incidence of amelogenesis imperfecta is uncertain. Estimates vary widely, from 1 in 700 people in northern Sweden to 1 in 14,000 people in the United States.
What genes are related to amelogenesis imperfecta?
Mutations in the AMELX, ENAM, and MMP20 genes cause amelogenesis imperfecta.
The AMELX, ENAM, and MMP20 genes provide instructions for making proteins that are essential for normal tooth development. These proteins are involved in the formation of enamel, which is a hard, calcium-rich material that forms the protective outer layer of each tooth. Mutations in any of these genes alter the structure of these proteins or prevent the genes from making any protein at all. As a result, tooth enamel is abnormally thin or soft and may have a yellow or brown color. Teeth with defective enamel are weak and easily damaged.
Researchers are looking for mutations in other genes that may also cause amelogenesis imperfecta.
How do people inherit amelogenesis imperfecta?
Amelogenesis imperfecta can have different inheritance patterns depending on the gene that is altered. Most cases are caused by mutations in the ENAM gene and are inherited in an autosomal dominant pattern. This type of inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder.
Amelogenesis imperfecta is also inherited in an autosomal recessive pattern; this form of the disorder can result from mutations in the ENAM or MMP20 gene. Autosomal recessive inheritance means two copies of the gene in each cell are altered.
About 5 percent of amelogenesis imperfecta cases are caused by mutations in the AMELX gene and are inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In most cases, males with an X-linked form of this condition experience more severe dental abnormalities than affected females.
Other cases of this condition result from new gene mutations and occur in people with no history of the disorder in their family.
Source: National Institutes of Health
Recent Amelogenesis Imperfecta News and Articles
Reports from Pontifical University Add New Data to Research in Genetics and Molecular Biology
2012 OCT 30 (NewsRx) -- By a News Reporter-Staff News Editor at Life Science Weekly
-- Investigators publish new report on Genetics and Molecular Biology. According to news originating from Bogota, Colombia, by NewsRx correspondents, research stated, "In this study, we analyzed the phenotype
, clinical characteristics and presence of mutations in the enamelin gene
ENAM in five Colombian families with autosomal dominant amelogenesis imperfecta
(ADAI). 22 individuals (15 affected and seven unaffected) belonging to five Colombian families with ADAI and eight individuals (three affected and five unaffected) belonging to three Colombian families with autosomal
recessive amelogenesis imperfecta (ARAI) that served as controls for molecular alterations and inheritance patterns were studied. Clinical, radiographic and genetic
evaluations were done in all individuals."
Our news journalists obtained a quote from the research from Pontifical University, "Eight exons and three intron-exon boundaries were sequenced for mutation analysis. Two of the five families with ADAI had the hypoplasic phenotype, two had the hypocalcified phenotype and one had the hypomaturative phenotype. Anterior open bite and mandibular retrognathism were the most frequent skeletal abnormalities in the families with ADAI. No mutations were found. These findings suggest that ADAI in these Colombian families was unrelated to previously described mutations in the ENAM gene."
According to the news editors, the research concluded: "These results also indicate that other regions not included in this investigation, such as the promoter region, introns and other genes should be considered as potential ADAI candidates."
For more information on this research see: Clinical and molecular analysis of the enamelin gene ENAM in Colombian families with autosomal dominant amelogenesis imperfecta. Genetics and Molecular Biology, 2012;35(3):557-66.
The news correspondents report that additional information may be obtained from S. Gutierrez, Dental Research Center, Faculty of Dentistry, Pontificia Universidad Javeriana, Bogota, Colombia.
Keywords for this news article include: Bogota, Colombia, South America, Tooth Diseases, Tooth Abnormalities, Amelogenesis Imperfecta, Stomatognathic Diseases, Congenital Abnormalities, Dental Enamel Hypoplasia, Genetics and Molecular Biology, Stomatognathic System Abnormalities.
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