Is Freeman-Sheldon Syndrome Dominant or Recessive?

Medically Reviewed on 2/2/2023
Freeman-Sheldon Syndrome
Those with Freeman-Sheldon syndrome may have severe physical limitations and need assistance with daily activities.

Freeman-Sheldon syndrome is inherited either as an autosomal dominant or autosomal recessive disorder.

Freeman-Sheldon syndrome is caused by mutations in the MYH3 gene, which is responsible for the production of the protein myosin-3. This protein plays a role in the development of muscle tissue.

The inheritance pattern of Freeman-Sheldon syndrome is complex and can vary from one family to another.

  • The autosomal dominant pattern of inheritance means that a person requires the inheritance of only one copy of the mutated MYH3 gene from one parent to develop the condition.
  • The autosomal recessive pattern of inheritance means that a person requires the inheritance of two copies of the mutated MYH3 gene, one from both parents, to develop the condition.
  • In some cases, Freeman-Sheldon syndrome could be caused by a spontaneous mutation in the MYH3 gene during fetal development. In these cases, the condition is not inherited from a parent.

What is Freeman-Sheldon syndrome?

Freeman-Sheldon syndrome (FSS) is also called whistling face syndrome, arthrogryposis type-2A (DA2A), etc. FSS is related to distal arthrogryposis type-1 (DA1), and it is described as congenital myopathy. It is a rare inherited disorder majorly affecting the bones and muscles in the face, hands, and feet. Eventually, it affects the overall growth and development of the body.

It is estimated that approximately 100 to 300 individuals could be affected with Freeman-Sheldon syndrome worldwide.

The facial features of individuals with FSS can include a small, downturned mouth with puckered skin around the mouth, widely spaced teeth, and a small chin. Abnormalities in the hands and foot, including underdeveloped fingers and toes, are seen. Individuals with FSS may have muscle weakness and problems with movement and respiratory function.

What are the signs and symptoms of Freeman-Sheldon syndrome?

The type and extent of the deformities may vary widely. Some individuals with Freeman-Sheldon syndrome (FSS) may have severe physical limitations and need assistance with daily activities. Others could have milder symptoms and be able to lead relatively normal lives.

The most common symptoms of FSS may include:

  • Short stature
  • Distinctive facial features
    • Small, upturned nose
    • Thin upper lip
    • Smallmouth
    • High-arched palate
    • Small chin
    • Narrow triangular face
    • Hypertelorism (wide space between the eyes)
    • Facial asymmetries
    • Angulated ears on the back of the head
    • Weakened facial muscles
  • Abnormalities of the hands and feet
    • Claw-like deformities of the fingers and toes
    • Webbing of the fingers and toes
    • Overlapping fingers
    • Ulnar deviation
    • Camptodactyly (permanent bending of one or more fingers)
    • Clubbing of foot (talipes equinovarus)
    • Overlapping toes
    • Tarsal fusion
    • Vertical talus
    • Valgus
  • Contractures (permanent shortening and stiffness of the joints and muscles)
    • Neck
    • Shoulders
    • Elbows
    • Wrists
    • Hips
    • Knees
    • Ankles
  • Abnormalities of the muscles of the eye
  • Scoliosis
  • Speech impairment

How is Freeman-Sheldon syndrome diagnosed?

The characteristic anatomical abnormalities of the face, hands, and legs will give an idea of the possible diagnosis of musculoskeletal disorder.

The disease is confirmed based on the results of the following tests:

  • Imaging tests, such as X-rays or CT scans, to get a better view of the bones and soft tissues in the affected areas.
  • A genetic test could be ordered to confirm the diagnosis of Freeman-Sheldon syndrome. This test involves analyzing a sample of the DNA to look for mutations in the MYH3 gene.
  • Antenatal diagnosis: Ultrasonography after 24 weeks of pregnancy can diagnose FSS. Some pregnant persons may experience reduced fetal activity without any apparent cause or complications if the fetus has FSS.

What are the treatment options for Freeman-Sheldon syndrome?

There is no cure for Freeman-Sheldon syndrome, but treatment may help improve mobility and function to improve the quality of life.

Treatment options for Freeman-Sheldon syndrome include:

  • Surgery: To correct abnormalities in the face. Some of them include:
    • Orthognathic surgery: Corrects abnormalities in the jaw, such as micrognathia (a small or underdeveloped lower jaw). It may involve moving the jawbone into a more normal position and reshaping the bones to improve the appearance and function of the face.
    • Orbitopathy surgery: Corrects abnormalities in the eye sockets, such as shallow eye sockets or misaligned eyes. It may involve reshaping the bones around the eye sockets to improve the appearance and function of the eyes.
    • Soft tissue surgery: Corrects abnormalities in the soft tissues of the face, such as excess skin or abnormal placement of the lips. It may involve removing excess skin or repositioning the lips to improve the appearance and function of the face.
  • Physical therapy: Helps improve mobility and strengthens the muscles in the hands, feet, and other affected areas.
  • Occupational therapy: Helps individuals with Freeman-Sheldon syndrome learn and perform daily activities, such as dressing, eating, and writing.
  • Orthopedic devices: Splints or braces may support the hands, feet, or other affected areas and improve mobility.
  • Speech therapy: Improves speech impairment caused by abnormalities in the facial muscles.
Medically Reviewed on 2/2/2023
Image Source: iStock image

Freeman-Sheldon syndrome.

Arthrogryposis, Distal, Type 2a (DA2A).