Freeman-Sheldon syndrome

Freeman-Sheldon syndrome (also known as Freeman-Burian syndrome) is a condition that primarily affects muscles in the face and skull (craniofacial muscles) and can often affect joints in the hands and feet. The condition is characterized by abnormalities known as contractures, which result from permanent tightening of muscles, skin, tendons, and surrounding tissues, and restrict movement of the affected body part. In Freeman-Sheldon syndrome, contractures in the face lead to a distinctive facial appearance including a small mouth (microstomia) with pursed lips, giving the appearance of whistling. For this reason, Freeman-Sheldon syndrome is sometimes called "whistling face syndrome." Other facial features common in this condition include a chin dimple shaped like an "H" or "V" and unusually deep folds in the skin between the nose and the corners of the mouth (nasolabial folds).

People with Freeman-Sheldon syndrome may also have a variety of other facial features, such as a prominent forehead and brow ridges, a sunken appearance of the middle of the face (midface hypoplasia), a short nose, a long area between the nose and mouth (philtrum), and full cheeks. Affected individuals may have a number of abnormalities that affect the eyes. These features can include widely spaced eyes (hypertelorism), deep-set eyes, outside corners of the eyes that point downward (down-slanting palpebral fissures), a narrowing of the eye opening (blepharophimosis), droopy eyelids (ptosis), and eyes that do not look in the same direction (strabismus).

Other features that can occur in Freeman-Sheldon syndrome include an unusually small tongue (microglossia) and jaw (micrognathia) and a high arch in the roof of the mouth (high-arched palate). People with Freeman-Sheldon syndrome may have difficulty swallowing (dysphagia), a failure to gain weight and grow at the expected rate (failure to thrive), and breathing complications that may be life-threatening. Speech problems or hearing impairment can also occur in people with this disorder.

In people with Freeman-Sheldon syndrome, contractures in the hands and feet can lead to permanently bent fingers and toes (camptodactyly), a hand deformity in which all of the fingers are angled outward toward the fifth finger (ulnar deviation, also called "windmill vane hand"), and inward- and downward-turning feet (clubfoot). Less commonly, contractures affect the hips, knees, shoulders, or elbows.

People with Freeman-Sheldon syndrome may also have abnormalities of the spine, ribs, or chest. Many affected individuals have abnormal side-to-side or front-to-back curvature of the spine (scoliosis or kyphosis) or an abnormally curved lower back (lordosis). In many affected individuals, the muscles between the ribs do not function properly, which can impair breathing or coughing. The ribs or breastbone (sternum) may be abnormally shaped in people with this condition.

Intelligence is unaffected in most people with Freeman-Sheldon syndrome, but development of normal milestones may be delayed due to physical abnormalities.