Orodental phenotype and genotype findings in all subtypes of hypophosphatasia.
BACKGROUND
Hypophosphatasia (HP) is a rare inherited disorder characterized by a wide spectrum of defects in mineralized tissues and caused by deficiency in the tissue non-specific alkaline phosphatase gene (ALPL). The symptoms are highly variable in their clinical expression, and relate to numerous mutations in this gene. The first clinical sign of the disease is often a premature loss of deciduous teeth, mostly in the moderate forms.


OBJECTIVE
The purpose of this study was to document the oral features of HP patients and to relate theses features to the six recognized forms of HP in 5 patients with known genotype and to investigate the genotype-phenotype correlations.


METHODS
Clinical and radiographic examinations were carried out. We collected medical and dental history in the kindred and biochemical data. Finally, mutations in the ALPL gene were tested by DNA sequencing in SESEP laboratory.


RESULTS
We have for the first time related the known dental anomalies which occur as integral features of HP to the recognized clinical forms of HP. We also pointed out striking dental abnormalities which were never described in association with this rare disease. Accurate genotype-phenotype severity correlations were observed.


CONCLUSIONS
This work allowed us to compare orodental manifestations in all the clinical forms of HP within the patient's sample. According to the severity of the disorder, some dental defects were infrequent, while other were always present. The long term prognosis of the permanent teeth varies from a patient to another. As premature loss of primary teeth is often the first, and sometimes the only visible symptom of the milder forms, the paediatric dentist plays a critical role in the detection and diagnosis of the disease.
Reibel
Amélie
A
Department of Paediatric Dentistry, Faculty of Dentistry, University of Strasbourg, France. ame.reibel@wanadoo.fr
Manière
Marie-Cécile
MC
Clauss
François
F
Droz
Dominique
D
Alembik
Yves
Y
Mornet
Etienne
E
Bloch-Zupan
Agnès
A
D000328:Adult; D000469:Alkaline Phosphatase / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005838:Genotype; D006801:Humans; D007014:Hypophosphatasia / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology*; D007223:Infant; D008297:Male; D009154:Mutation; D010641:Phenotype; D011859:Radiography; D017422:Sequence Analysis, DNA; D012720:Severity of Illness Index; D014071:Tooth Abnormalities / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology*
D000469:Alkaline Phosphatase