INTRODUCTION
Axenfeld-Rieger syndrome (ARS) is a rare autosomal dominant disorder with complete penetration and variable expressivity (1). The first description of the inherited syndrome was in 1935 by Rieger (2, 3). Different estimated incidence has been described 1:200.000 (2), 1:50.000 to 1:100.000 (1). 70% of the cases are inherited and 30% are arising de novo (4). ARS has variable expressivity and it is considered to be a heterogeneous disorder both morphologically and genetically (2, 3, 5). There is not reported any racial or sexual predilection (6, 7) and the syndrome has been described in different ethnic groups, including Asia, Middle East, South and North America, Africa and Europe (1).
ARS is a combination of anterior chamber cleavage syndrome and nonocular abnormalities (8). Since 1989 (9) the term ARS has been used collectively for, Axenfeld’s syndrome, Axenfeld’s anomaly, Rieger’s anomaly and Rieger’s syndrome (10). An overview is giving in table 1 with a description of the different anomalies and syndromes according to Bender et al. (10). ARS is characterized as a syndrome with malformation of the anterior segment of the eye in combination with a wide spectrum of non-ocular abnormalities such as dental, craniofacial and somatic abnormalities. The wide range of clinical presentation and developmental disturbances is described by many authors in the literature (2-8, 11, 12) and is listed in table 2. Hypodontia and failure of the periumbilical skin to involute is most frequently seen (3, 7, 8). A change in the periumbilical skin can be wrongly diagnosed as umbilical hernia and lead to unnecessary surgery (1).
Pathogenesis of ARS is assumed to be a genetic failure that results in development disturbance in the late gestation period. A defect in the ectodermal tissue due to a change in migration and differentiation of the neural crest tissue is thought to be the cause (8, 9). The neural crest cells are responsible for the formation of the craniofacial and ocular structures including bones, cartilage, dental papillae, pituitary gland and the umbilical ring (7). ARS is in the literature (1, 13) divided in to three different types, due to different genetic mutations and deletions (14, 15) combined with different ocular and systemic expressions see table 3.
The aim of this study is to present to two families with Axenfeld-Rieger Syndrome, present their clinical findings, treatment of the dental anomalies and dentofacial deformities.