Mutational spectrum of FAM83H: the C-terminal portion is required for tooth enamel calcification.
Dental enamel forms through the concerted activities of specialized extracellular matrix proteins, including amelogenin, enamelin, MMP20, and KLK4. Defects in the genes encoding these proteins cause non-syndromic inherited enamel malformations collectively designated as amelogenesis imperfecta (AI). These genes, however, account for only about a quarter of all AI cases. Recently we identified mutations in FAM83H that caused autosomal dominant hypocalcified amelogenesis imperfecta (ADHCAI). Unlike other genes that cause AI, FAM83 H does not encode an extracellular matrix protein. Its location inside the cell is completely unknown, as is its function. We here report novel FAM83H mutations in four kindreds with ADHCAI. All are nonsense mutations in the last exon (c.1243G>T, p.E415X; c.891T>A, p.Y297X; c.1380G>A, p.W460X; and c.2029C>T, p.Q677X). These mutations delete between 503 and 883 amino acids from the C-terminus of a protein normally comprised of 1179 residues. The reason these mutations cause such extreme defects in the enamel layer without affecting other parts of the body is not known yet. However it seems evident that the large C-terminal part of the protein is essential for proper enamel calcification.
Lee
Sook-Kyung
SK
Department of Cell and Developmental Biology & Dental Research Institute, School of Dentistry, Seoul National University, 275-1 Yongon-dong, Chongno-gu, Seoul 110-768, Korea.
Hu
Jan C-C
JC
Bartlett
John D
JD
Lee
Kyung-Eun
KE
Lin
Brent P-J
BP
Simmer
James P
JP
Kim
Jung-Wook
JW
D000293:Adolescent; D000567:Amelogenesis Imperfecta / Q000235:genetics; D002648:Child; D004252:DNA Mutational Analysis; D005091:Exons; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005799:Genes, Dominant; D006801:Humans; D008297:Male; D008957:Models, Genetic; D010641:Phenotype; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000235:genetics* / Q000502:physiology; D014074:Tooth Calcification / Q000235:genetics*
C527308:FAM83H protein, human; D011506:Proteins