It is an autosomal recessive osteochondrodysplastic disease with typical skeletal anomalies and high mortality in the first year of life. It is part of a group of disease involved with multiple dislocations and characterized by severe prenatal and postnatal growth retardation (dwarfism < 5 SD), joint laxity, very short extremities, and progressive scoliosis.
Desbuquois Dysplasia; DBQD; Desbuquois Grenier Michel Syndrome; Micromelic Dwarfism with Vertebral and Metaphyseal Abnormalities and Advanced Carpotarsal Ossification Syndrome.
This medical condition was first described in 1966 by G. Desbuquois, a French pediatrician, when he and his colleagues studied and reported the disease in two sisters.
There are two types of Desbuquois Dysplasia and one variant that have been described in the literature. Desbuquois dysplasia is clinically and radiographically heterogeneous, and the two types are based on the presence (Type 1) or absence (Type 2) of characteristic hand anomalies.
Desbuquois Dysplasia Type I: Characterized by an extra ossification center distal to the second metacarpal, delta phalanx, bifid distal thumb phalanx, and dislocation of the interphalangeal joints.
Desbuquois Dysplasia Type II: Presents all clinical features except the hand anomalies described for Type I.
Kim Variant of Desbuquois Dysplasia DBQD: Described in seven patients originating from Korea and Japan. It is characterized by short stature, joint anomalies, minor facial malformations, and significant hand anomalies with short metatarsal bones, fusiform and long fingers, and advanced bone age. Although it is often classified as a Desbuquois Dysplasia Type I, the hand anomalies are radiologically different and clinically show very short metacarpals, elongated phalanges, and remarkably advanced carpal bone age, which is not present in Type I. Finally, the Kim variant does not have the accessory ossification center distal to the second metacarpal, as well as thumb anomalies.
The exact incidence remains unknown. Both males and females seem to be equally affected. Affected individuals are of all racial and ethnic groups worldwide. The Kim Variant of Desbuquois Syndrome has been observed among Korean and Japanese descents. Approximately 40 cases have been described in the literature thus far.
It is inherited as autosomal recessive trait. Type 1 and Kim variant are caused by mutations in the CANT1 gene that is located on chromosome 17q25.3. The mutations involved in Type 2 are located in the XYLT1 gene on chromosome16p12; however, in few cases no cause has been identified, suggesting other unidentified genes may be part of the syndrome.
Advance in molecular genetics has allowed to understand better the origin of this medical condition. However, the pathophysiology for this severe form of dwarfism and its musculoskeletal specificities remains unknown. Because of a strong radiologic similarity with diastrophic dysplasia, abnormalities in the diastrophic dysplasia ...