EDAR-induced hypohidrotic ectodermal dysplasia: a clinical study on signs and symptoms in individuals with a heterozygous c.1072C > T mutation

Background: Mutations in the EDAR-gene cause hypohidrotic ectodermal dysplasia, however, the oral phenotype has been described in a limited number of cases. The aim of the present study was to clinically describe individuals with the c. 1072C > T mutation (p. Arg358X) in the EDAR gene with respect to dental signs and saliva secretion, symptoms from other ectodermal structures and to assess orofacial function. Methods: Individuals in three families living in Sweden, where some members had a known c. 1072C > T mutation in the EDAR gene with an autosomal dominant inheritance (AD), were included in a clinical investigation on oral signs and symptoms and self-reported symptoms from other ectodermal structures (n = 37). Confirmation of the c. 1072C > T mutation in the EDAR gene were performed by genomic sequencing. Orofacial function was evaluated with NOT-S. Results: The mutation was identified in 17 of 37 family members. The mean number of missing teeth due to agenesis was 10.3 +/- 4.1, (range 4-17) in the mutation group and 0.1 +/- 0.3, (range 0-1) in the non-mutation group (p < 0.01). All individuals with the mutation were missing the maxillary lateral incisors and one or more of the mandibular incisors; and 81.3% were missing all four. Stimulated saliva secretion was 0.9 +/- 0.5 ml/min in the mutation group vs 1.7 +/- 0.6 ml/min in the non-mutation group (p < 0.01). Reduced ability to sweat was reported by 82% in the mutation group and by 20% in the non-mutation group (p < 0.01). The mean NOT-S score was 3.0 +/- 1.9 (range 0-6) in the mutation group and 1.5 +/- 1.1 (range 0-5) in the non-mutation group (p < 0.01). Lisping was present in 56% of individuals in the mutation group. Conclusions: Individuals with a c. 1072C > T mutation in the EDAR-gene displayed a typical pattern of congenitally missing teeth in the frontal area with functional consequences. They therefore have a need for special attention in dental care, both with reference to tooth agenesis and low salivary secretion with an increased risk for caries. Sweating problems were the most frequently reported symptom from other ectodermal structures.