EDA gene defects cause ectodermal dysplasia, which is also known as X-linked hypohidrotic ectodermal dysplasia. Common dental features of ectodermal dysplasia are multiple missing teeth and microdontia.PAX9 and TGFA are involved in regulating between MSX1 and PAX9, causing hypodontia of the molars.Hypodontia can be found in isolated cases too. The familiar or sporadic type of isolations are more frequently reported than the syndromic type. Isolated cases of autosomal dominant, autosomal recessive, or X-linked inheritance patterns may have an impact on the isolation conditions in expressing variation of both penetration and expressivity of traits. Mutations in MSX, PAX9 and TGFA genes are known to cause congenitally missing teeth in some racial groups. Research
In the 1960s and 1970s, several studies were conducted sponsored by the U.S. Atomic Energy Commission, with the aim of finding a link between genetics and hypodontia. Impact
There are numerous studies and research reports on the prevalence, aetiology, and treatment of hypodontia and the dentoskeletal effect of hypodontia. A few studies have investigated Oral Health-related Quality of Life (OHRQoL) in individuals with hypodontia and provided some evidence that hypodotia may have an impact on quality of life. Psychosocial
Cosmetic dentistry has become more notable and prevalent in modern society. Interpersonal relationships and perceived qualities, such as intelligence, friendliness, social class, and popularity can be affected by dentofacial appearance.
In 20 patients (12 and 8 probands, respectively), missense mutations (R672H; MIM *160270.0001 and R672C; MIM *160270.0002) caused substitution of arg672, an embryonic myosin residue retained post-embryonically. Of the remaining 6 patients in whom they found mutations, 3 had missense private de novo (E498G; MIM *160270.0006 and Y583S) or familial mutations (V825D; MIM *160270.0004); 3 other patients with sporadic expression had de novo mutations (T178I; MIM *160270.0003), which was also found in DA2B; 2 patients had no recognized mutations. Diagnosis
Freeman–Sheldon syndrome is a type of distal arthrogryposis, related to distal arthrogryposis type 1 (DA1). In 1996, more strict criteria for the diagnosis of Freeman–Sheldon syndrome were drawn up, assigning Freeman–Sheldon syndrome as distal arthrogryposis type 2A (DA2A).On the whole, DA1 is the least severe; DA2B is more severe with additional features that respond less favourably to therapy. DA2A (Freeman–Sheldon syndrome) is the most severe of the three, with more abnormalities and greater resistance to therapy.Freeman–Sheldon syndrome has been described as a type of congenital myopathy.In March 2006, Stevenson et al. published strict diagnostic criteria for distal arthrogryposis type 2A (DA2A) or Freeman–Sheldon syndrome. These included two or more features of distal arthrogryposis: microstomia, whistling-face, nasolabial creases, and H-shaped chin dimple. Management
Surgical and anesthetic considerations
Patients must have early consultation with craniofacial and orthopaedic surgeons, when craniofacial, clubfoot, or hand correction is indicated to improve function or aesthetics. Operative measures should be pursued cautiously, with avoidance of radical measures and careful consideration of the abnormal muscle physiology in Freeman–Sheldon syndrome.