Fahr's Syndrome with Pseudohypoparathyroidism: Oral Features and Genetic Insights

Fahr's syndrome is a rare neurodegenerative disorder with limited research on its oral manifestations. This study investigates the dental features and genetic background of Fahr's syndrome through a pedigree analysis and a retrospective literature study. A clinical examination and whole-exome sequencing (WES) were conducted on a female patient with Fahr's syndrome and pseudohypoparathyroidism, along with her family members. The patient presented with super-numerary teeth, tooth agenesis, enamel hypoplasia, and abnormal tooth eruption. The WES did not reveal any known pathogenic mutations related to pseudohypoparathyroidism or Fahr's disease. However, genetic variations in KIF1A, FZD8, and PDGFA may underlie these dental abnormalities. Additionally, a retrospective analysis of 22 reported cases from PubMed and the Human Gene Mutation Database (1 January 1965-30 June 2024) was conducted with keywords such as "Fahr's disease", "Fahr's syndrome", "dental", and "hypoparathyroidism". The analysis showed that patients with Fahr's syndrome, pseudohypoparathyroidism, and idiopathic hypoparathyroidism exhibited similar oral abnormalities, including tooth agenesis, root dysplasia, dental malformations, and abnormal tooth eruption. Variations in the incidence of tooth agenesis and dental malformation among these groups may be linked to differences in parathyroid hormone metabolism. These findings suggest oral abnormalities are the key local features of Fahr's syndrome and related parathyroid disorders.