This rare inherited genetic condition presents abnormalities of several parts of the body such as the limbs, face, head and the skeletal system. This syndrome is also known as whistling face syndrome and craniocarpotarsal dystrophy. As this is a rare syndrome, the exact prevalence of this condition is not known.
Causes
Freeman-sheldon syndrome occurs as the result of mutations in the gene MYH3 which is essential for the production of a protein known as embryonic skeletal muscle myosin heavy chain 3. This protein is important for the transportation of materials between and within cells. The embryonic skeletal muscle myosin is required for the development of the muscles and the genetic mutation results in the disruption of its function. Hence, the muscle cells of the fetus are not able to contract as effectively which affects the muscle development. As the result, the various problems of the muscle and the skeletal system are evident. This condition can be inherited in autosomal dominant pattern where one copy of the genetic mutation can cause this syndrome and the autosomal recessive pattern when both the copies of the genes in each cell are defective.
Symptoms
As the features of this condition are evident at the birth of the infant, the severity varies greatly between the affected individuals. Some of the characteristics of this condition include a flat face, a small mouth, underdeveloped nose cartilage, club feet, contracted muscles of the fingers joints and the hands. They may also have improperly aligned teeth, high roof of the mouth and a small tongue. The abnormalities of the mouth and the jaw can create problems with suckling, eating, failure to grow at expected rate, poor weight gain and respiratory complications. They may also have wide spaced eyes (ocular hypertelorism), crossed eyes (strabismus), downward slanting eyelid folds (palpebral fissures) and droopy eyelids (ptosis). In addition, they may also exhibit front-to-back and side-to-side curvature of the spine, dislocation of the hips, epileptic seizures, hearing loss, protrusion of the intestine in an abnormal opening and degeneration of the muscles of the lower legs.
Diagnosis
The diagnosis of this syndrome before the birth of the infant is possible with the ultrasonography assessment as early as 20 weeks pregnancy. Freeman-sheldon syndrome can also be confirmed after the birth through identifying the features that are characteristic of this condition. Various imaging techniques may be necessary to determine the severity of the various craniofacial and dental symptoms that includes computed tomography (CT) scans and X-rays. In some of the cases, a biopsy of the muscle tissue may be required to identify the fibrous connective tissue abnormalities.
Treatment
The treatment is based on the various symptoms that are evident in each of the cases and are symptomatic or supportive. A surgery may be required to treat the unusually small mouth, club feet, hand and craniofacial abnormalities. Speech therapy and physical therapy may improve the speech, swallowing and the individual’s ability to walk independently. Genetic counseling may benefit some of the affected individuals and their family.
References
https://rarediseases.org/rare-diseases/freeman-sheldon-syndrome/
http://syndrome.org/freeman-sheldon-syndrome/
https://ghr.nlm.nih.gov/condition/freeman-sheldon-syndrome#inheritance
