Novel PAX9 and COL1A2 missense mutations causing tooth agenesis and OI/DGI without skeletal abnormalities.

[dentin dysplasia]

Inherited dentin defects are classified into three types of dentinogenesis imperfecta (DGI ) and two types of dentin dysplasia (DD ). The genetic etiology of DD-I is unknown . Defects in dentin sialophosphoprotein (DSPP ) cause DD type II and DGI types II and III . DGI type I is the oral manifestation of osteogenesis imperfecta (OI ), a systemic disease typically caused by defects in COL 1 A 1 or COL 1 A 2 . Mutations in MSX 1 , PAX 9 , AXIN 2 , EDA and WNT 10 A can cause non-syndromic familial tooth agenesis . In this study a simplex pattern of clinical dentinogenesis imperfecta juxtaposed with a dominant pattern of hypodontia (mild tooth agenesis ) was evaluated , and available family members were recruited . Mutational analyses of the candidate genes for DGI and hypodontia were performed and the results validated . A spontaneous novel mutation in COL 1 A 2 (c .1171 G >A ; p .G ly 391 S er ) causing only dentin defects and a novel mutation in PAX 9 (c .43 T >A ; p .Phe 15 Ile ) causing hypodontia were identified and correlated with the phenotypic presentations in the family . Bone radiographs of the proband 's dominant leg and foot were within normal limits . We conclude that when no DSPP mutation is identified in clinically determined isolated DGI cases , COL 1 A 1 and COL 1 A 2 should be considered as candidate genes . PAX 9 mutation p .Phe 15 Ile within the N-terminal Î²-hairpin structure of the PAX 9 paired domain causes tooth agenesis .

Diseases
Validation

Diseases presenting "spontaneous novel mutation" symptom

dentin dysplasia

dentinogenesis imperfecta

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