RAPADILINO syndrome

RAPADILINO syndrome is a rare inherited condition that involves many parts of the body, with bone development especially affected. Most affected people have underdeveloped or absent bones in the forearms and thumbs, known as radial ray malformations, and the kneecaps may also be small or missing. Other features include a cleft or high arched palate, a long slender nose and dislocated joints. Many infants have difficulty feeding, with diarrhea and vomiting, and together with the skeletal changes this leads to slow growth and short stature. Some people have harmless light brown skin patches resembling cafe-au-lait spots, and there is a slightly increased risk of osteosarcoma, usually in childhood or adolescence, and of lymphoma, typically in young adulthood. The name is an acronym of its characteristic features: radial ray malformations, patella and palate abnormalities, diarrhea and dislocated joints, limb abnormalities and little size, and slender nose with normal intelligence. The condition is caused by mutations in the RECQL4 gene and is inherited in an autosomal recessive pattern. It was first identified in Finland, where it affects an estimated 1 in 75,000 people, and has since been found in other regions. Its features overlap with Baller-Gerold syndrome and Rothmund-Thomson syndrome, which can be caused by mutations in the same gene, and researchers are investigating whether the three are separate disorders or one syndrome with overlapping signs and symptoms.