Dyssegmental dysplasia, Rolland-Desbuquois type

Dyssegmental dysplasia, Rolland-Desbuquois type (also known as dyssegmental dysplasia, mild type) is a rare autosomal recessive skeletal dysplasia characterized by severe short-limbed dwarfism with vertebral segmentation abnormalities. It is caused by mutations in the HSPG2 gene, which encodes perlecan, a major heparan sulfate proteoglycan of basement membranes and cartilage. Unlike the more severe Silverman-Handmaker type, the Rolland-Desbuquois type is generally compatible with survival beyond the neonatal period. The condition primarily affects the skeletal system. Key clinical features include disproportionate short stature with short limbs (micromelia), anisospondyly (vertebral bodies of varying size and shape), narrow thorax, flattened vertebral bodies, bowing of long bones, and joint contractures or limited joint mobility. Cleft palate, micrognathia, and encephalocele have also been reported in some cases. Radiographic findings typically reveal irregular vertebral segmentation, metaphyseal widening, and reduced ossification of certain skeletal elements. There is no specific cure or targeted therapy for dyssegmental dysplasia, Rolland-Desbuquois type. Management is supportive and multidisciplinary, focusing on orthopedic interventions for skeletal deformities, respiratory support if the narrow thorax compromises breathing, and surgical correction of cleft palate when present. Physical therapy may help manage joint contractures. Genetic counseling is recommended for affected families. Long-term prognosis varies, but individuals with this type generally have a better outcome compared to the Silverman-Handmaker type, with many surviving into childhood and beyond.

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