Tooth Agenesis, Selective, 8

A number sign (#) is used with this entry because of evidence that selective tooth agenesis-8 (STHAG8) is caused by heterozygous mutation in the WNT10B gene (601906) on chromosome 12q13.

For a general phenotypic description and a discussion of genetic heterogeneity of selective tooth agenesis, see STHAG1 (106600).

Clinical Features

Yu et al. (2016) studied a Chinese family in which a mother and her daughter and son exhibited oligodontia, with 12 to 24 missing teeth. The existing teeth were small and/or cone-shaped. All 3 affected individuals had sparse eyebrows, and the children also had sparse light-brown hair as well as dry skin. The authors stated that there were no obvious developmental abnormalities of the ears, hands, or feet in the affected members of the family.

Molecular Genetics

In a Chinese family in which a mother and her daughter and son exhibited oligodontia but had no mutation in known oligodontia-associated genes, Yu et al. (2016) performed whole-exome sequencing and identified heterozygosity for a missense mutation in the WNT10B gene (R211Q; 601906.0003) that segregated fully with disease in the family. Screening the WNT10B gene in a cohort of 145 probands with oligodontia revealed 3 more patients with heterozygous mutations, including 2 missense and 1 nonsense mutation (W262X; 601906.0004). Functional analysis demonstrated that the mutants could not efficiently induce endothelial differentiation of dental pulp stem cells. Yu et al. (2016) observed that the most frequently missing permanent teeth in WNT10B-associated oligodontia were the lateral incisors (83.3%), whereas premolars were missing only 51.4% of the time, which they noted was a pattern 'clearly different' from the oligodontia patterns resulting from WNT10A (606268) mutations (see STHAG4, 150400); however, they suggested that an overlapping phenotype in some individuals with WNT10A or WNT10B mutations was likely.