ABSTRACT
Amelogenesis imperfecta (AI) is a heterogeneous group of inherited defects in dental enamel formation. The malformed enamel can be unusually thin, soft, rough and stained. The strict definition of AI includes only those cases where enamel defects occur in the absence of other symptoms. Currently, there are seven candidate genes for AI: amelogenin, enamelin, ameloblastin, tuftelin, distal-less homeobox 3, enamelysin, and kallikrein 4. To identify sequence variations in AI candidate genes in patients with isolated enamel defects, and to deduce the likely effect of each sequence variation on protein expression and structure, families with isolated enamel defects were recruited. The coding exons and nearby intron sequences were amplified for each of the AI candidate genes by using genomic DNA from the proband as template. The amplification products for the proband were sequenced. Then, other family members were tested to determine their genotype with respect to each sequence variation. All subjects received an oral examination, and intraoral photographs and dental radiographs were obtained. Out of 24 families with isolated enamel defects, only six disease-causing mutations were identified in the AI candidate genes. This finding suggests that many additional genes potentially contribute to the etiology of AI.
Subject(s)
Amelogenesis Imperfecta/genetics , Dental Enamel Proteins/genetics , Mutation/genetics , Amelogenin , Exons/genetics , Genotype , Homeodomain Proteins/genetics , Humans , Introns/genetics , Kallikreins/genetics , Matrix Metalloproteinase 20 , Matrix Metalloproteinases/genetics , Pedigree , Sequence Analysis, DNA , Transcription Factors/geneticsABSTRACT
In the course of establishing and evaluating a patient education program, we compared 4 strategies for locating patients with chronic obstructive airway disease (COAD): (1) search of hospital discharge records (HOSP), (2) referral by physicians (MD), (3) an advertising campaign (AD), and (4) a respiratory symptom questionnaire mailed to households (QUEST). Of 1,834 persons assessed, 923 (50%) had airway obstruction; 43% of the confirmed cases (396 of 923) reported no previous diagnosis of COAD. The HOSP strategy accounted for 75 assessments (4%) and 63 confirmed cases (7%), MD produced 352 assessments (19%) and 247 cases (27%), AD generated 475 assessments (26%) and 204 cases (22%), and QUEST resulted in 932 assessments (51%) and 409 cases (44%); MD was the least expensive strategy ($17.00/case). The mailed questionnaire located the largest number of cases not previously diagnosed.
