Aarskog syndrome is a very rare disease that affects a person's height, muscles, skeleton, genitals, and appearance. It can be passed down through families (inherited).

Aarskog disease; Aarskog-Scott syndrome; AAS; Faciodigitogenital syndrome; Gaciogenital dysplasia

Aarskog syndrome is a genetic disorder that is linked to the X chromosome. It affects mainly males, but females may have a milder form. The condition is caused by changes (mutations) in a gene called "faciogenital dysplasia" (FGD1).

Symptoms of this condition include:

• Belly button that sticks out
• Bulge in the groin or scrotum
• Delayed sexual maturity
• Delayed teeth
• Downward palpebral slant to eyes (palpebral slant is the direction of the slant from the inner to outer corner of the eye)
• Hairline with a "widow's peak"
• Mildly sunken chest (pectus excavatum)
• Mild to moderate cognitive problems
• Mild to moderate short height, which may not be obvious until the child is 1 to 3 years old
• Poorly developed middle section of the face
• Rounded face
• Scrotum surrounds the penis (shawl scrotum)
• Short fingers and toes with mild webbing
• Single crease in the palm of the hand
• Small, broad hands and feet with short fingers and curved-in fifth finger
• Small nose with nostrils tipped forward
• Testicles that have not come down (undescended)
• Top portion of the ear folded over slightly
• Wide groove above the upper lip, crease below the lower lip
• Wide-set eyes with droopy eyelids

These tests may be done:

• Genetic testing for mutations in the FGD1 gene
• X-rays

Moving the teeth may be done to treat some of the abnormal dental features a person with Aarskog syndrome may have.

More information and support for people with Aarskog syndrome and their families can be found at:

• National Organization for Rare Disorders -- rarediseases.org/rare-diseases/aarskog-syndrome
• NIH Genetic and Rare Diseases Information Center -- rarediseases.info.nih.gov/diseases/4775/aarskog-syndrome

Some people may have some mental slowness, but children with this condition often have good social skills. Some males may have problems with fertility.

These complications can occur:

• Changes in the brain
• Difficulty growing in the first year of life
• Poorly aligned teeth
• Seizures
• Undescended testicles

Contact your health care provider if your child has delayed growth or if you notice any symptoms of Aarskog syndrome. Seek genetic counseling if you have a family history of Aarskog syndrome. Contact a genetic specialist if your provider thinks you or your child may have Aarskog syndrome.

Genetic testing may be available for people with a family history of the condition or a known mutation of the gene that causes it.

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Haddad J. Congenital malformations of the ear. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 678.

Jones KL, Jones MC, Del Campo M. Moderate short stature, facial ± genital. In: Jones KL, Jones MC, Del Campo M, eds. Smith's Recognizable Patterns of Human Malformation. 8th ed. Philadelphia, PA: Elsevier; 2022:chap D.