Is Aarskog-Scott Syndrome a Genetic Disorder?

Medically Reviewed on 1/14/2022
Aarskog-Scott Syndrome
Aarskog-Scott syndrome is a rare X-linked genetic disorder that is caused by a genetic mutation in the FGD1 gene.

Aarskog-Scott syndrome, also called Aarskog disease or Aarskog syndrome (AAS), is an extremely rare X-linked genetic disorder. The term "X-linked" means that the defective gene causing this condition is located on the X chromosome.

This condition is caused by a genetic mutation in the FGD1 gene (fascial genital dysplasia).

  • The FGD1 gene codes for a protein that activates (turns on) another protein called Cdc42, which transmits signals important for various aspects of embryonic development and development after birth.
  • Mutations in the FGD1 gene result in the production of a protein that functions abnormally. These mutations interfere with Cdc42 signaling, resulting in the wide range of developmental abnormalities seen in Aarskog-Scott syndrome.
  • Aarskog syndrome is difficult to detect due to morphological defects until a child reaches the age of three years.
  • Aarskog syndrome is an inherited disorder that can run in families. It primarily affects males, but it has been reported in females as well. When AAS is diagnosed in women, the symptoms are generally milder than in men.
  • Only about 20 percent of people with this disorder have FGD1 gene mutations that can be identified. The cause of Aarskog-Scott syndrome in other people is unknown.

A woman who carries the faulty gene has a 25 percent chance of having a son with Aarskog syndrome. Fathers cannot pass on their faulty genes to their sons, but they can pass it on to their daughters, making them carriers.

What are the symptoms of Aarskog-Scott syndrome?

Patients with Aarskog-Scott syndrome have skeletal and mild to moderate mental abnormalities and morphological features abnormalities of body structures.

  • Growth
    • Mild to moderate short stature is evident by the age of one to three years
    • The adolescent growth spurt is delayed
  • Performance
  • Face
    • Rounded face
    • Widow's peak hairline
    • Hypertelorism (Wide-set eyes)
    • Blepharoptosis (Droopy eyelids)
    • Downslanting eyes
    • Small nose with nostrils tipped forward (anteverted)
    • Underdeveloped mid-portion of the face
    • Wide groove above the upper lip (broad philtrum)
    • Crease below the lower lip
    • Delayed eruption of teeth
    • The upper helix (top portion) of the ear folded over slightly
  • Hands and feet
    • Small, broad hands and feet
    • Brachydactyly (Short fingers and toes)
    • Clinodactyly (In-curving of the fifth finger)
    • Mild interdigital webbing, between fingers and toes
    • Single transverse "simian crease" in palm
    • Broad thumbs and big toes
  • Neck
    • Short neck
    • Webbing of sides of the neck
  • Chest
    • Mild pectus excavatum (sunken chest)
  • Abdomen
    • Protruding navel
    • Inguinal hernias
  • Genitalia
    • Shawl scrotum (scrotum surrounding the penis)
    • Undescended testicles

7 ways to diagnose Aarskog syndrome

Aarskog syndrome (AAS) is diagnosed by taking the medical history of the patient.

Other methods to diagnose AAS include:

  • A thorough physical examination that documents the various morphological feature abnormalities
  • FGD1 genetic testing in the lab
  • Skeletal X-rays may be required to reveal distinctive skeletal abnormalities
  • An echocardiogram may detect congenital heart defects (if any present)
  • A computed tomography scan of the brain may reveal cystic changes
  • An X-ray of the teeth may reveal poorly aligned teeth with delayed growth patterns
  • An ultrasound of the abdomen may reveal the presence of an undescended testis

Many clinical conditions can have symptoms that are similar to one another. To arrive at a definitive diagnosis, the doctor may order additional tests to rule out other clinical conditions.

What is the prognosis of patients with Aarskog-Scott syndrome?

The severity of the signs and symptoms determines the prognosis of Aarskog syndrome.

In general, affected individuals can manage their lives and integrate into society with minimal difficulty.

  • A mild decline in mental performance may be undetectable in daily interactions
  • Males affected by the syndrome may have lower fertility rates
  • If the individual has associated cardiac abnormalities, it can lead to heart failure
  • The presence of abnormal facial features can lead to low self-esteem
  • Short stature may result from a lack of growth development

6 treatment options for Aarskog-Scott syndrome

Aarskog-Scott syndrome, like all genetic diseases, cannot be cured, but there are numerous treatments available to improve quality of life. The goal of treatment is to alleviate the symptoms that are causing problems.

Treatment of Aarskog syndrome focuses on the specific symptoms that each person experiences and may necessitate the collaborative efforts of a team of specialists.

  • Pediatricians, surgeons, cardiologists, dental specialists, speech pathologists, audiologists (who assess and treat hearing problems), eye specialists, and other healthcare professionals may need to plan an affected child's treatment systematically and comprehensively.
  • Surgery may be required to treat specific congenital or structural malformations that are occasionally associated with Aarskog syndrome (hypospadias, inguinal or umbilical hernias, cryptorchidism, unusually severe craniofacial features).
  • Individuals with Aarskog syndrome should have comprehensive eye and dental exams. Growth hormone therapy has been shown to increase height in some children, but more research is needed to determine appropriate management and response expectations.
  • A neuropsychiatric evaluation and input may be indicated for the possibly neurodevelopmental symptoms.
  • Supportive care typically includes educational assistance for those suffering from mental deficiencies. Parents frequently require guidance and emotional support.
  • Affected individuals and their families should seek genetic counseling to better understand the genetic and clinical characteristics, inheritance, and recurrence risks of the condition in their families.
Medically Reviewed on 1/14/2022
Image Source: iStock Images

National Organization for Rare Disorders. Aarskog Syndrome.

Genetic and Rare Diseases Information Center. Aarskog syndrome.

Global Genes. Aarskog-Scott syndrome.