Freeman-Sheldon syndrome (FSS) is a very rare, congenital contractures syndrome characterized by dysmorphic status combining bone anomalies and joint contractures with typical facies features. FSS is the most severe form of distal arthrogryposes. Approximately 100 cases have been reported in the medical literature. It affects male and female equally. Symptoms and physical findings associated with this disorder are usually present at birth and vary greatly from case to case. The three basic abnormalities are microstomia with pouting lips, camptodactyly with ulnar deviation of the hand and talipes equinovarus. Other FSS symptoms include scoliosis, H-shaped dimpling of the chin, deep nasolabial folds, and blepharophimosis. Infants with FSS may suffer from dysphagia, failure to thrive, growth deficit, and life-threatening respiratory complications due to structural anomalies of the oropharynx and upper airways. Affected people also have an increased risk of developing malignant hyperthermia; a severe reaction to certain drugs used during surgery and other invasive procedures.
The diagnosis of FSS is based on the medical history and physical examination that reveal characteristic dysmorphic status combining bone anomalies and joint contractures with typical facies features.
Mutations in the MYH3 gene, located on 17p13.1, have been identified in patients with Freeman-Sheldon syndrome.