title: True oligodontia with microdontia in monozygous twins: implications for reappraisal of Butler's Field Theory.
abstract: Oligodontia, which may be defined as the congenital absence of six or more teeth apart from third molars, affects less than 0.5% of the population and may occur in isolation or as part of a syndrome. This paper aims to clarify the role of genetic factors in this condition by reporting a case of a pair of identical twins and their mother who display similar patterns of oligodontia without medical problems. Each twin has 13 missing permanent teeth and their mother 16 missing teeth, but the patterns of agenesis do not conform with Butler's Field Theory according to which the distal teeth in each class are most likely to be absent. Unerupted third molars are present in both twins and all three family members display maxillary lateral incisors. Dental crown size profile patterns were computed for all three individuals and highlight a marked reduction in mesiodistal and buccolingual dimensions of the remaining teeth in each. In addition, erupted teeth showed simplified crown morphology. Oligodontia should not be viewed in isolation, but rather considered as one manifestation of a variety of dental changes in genetically susceptible individuals.
authors.affiliation: Department of Anatomical Sciences, University of the Witwatersrand, Parktown, Johannesburg, RSA.
authors.forename: J K
authors.initials: JK
authors.lastname: Buckley
authors.forename: G A
authors.initials: GA
authors.lastname: Doran
mesh_terms: D000328:Adult; D000848:Anodontia / Q000235:genetics*; D001641:Bicuspid / Q000002:abnormalities; D002508:Cephalometry; D004200:Diseases in Twins; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007180:Incisor / Q000473:pathology; D008957:Models, Genetic; D008964:Molar, Third / Q000473:pathology; D009811:Odontometry; D014071:Tooth Abnormalities / Q000235:genetics*; D019228:Tooth Crown / Q000002:abnormalities; D014094:Tooth, Deciduous / Q000473:pathology; D014097:Tooth, Unerupted / Q000473:pathology; D014430:Twins, Monozygotic