Hanhart syndrome is a rare condition that primarily affects the craniofacial region and the limbs (arms and legs). People affected by this condition are often born with a short, incompletely developed tongue; absent or partially missing fingers and/or toes; abnormalities of the arms and/or legs; and an extremely small jaw. The severity of these physical abnormalities varies greatly among affected people, and children with this condition often have some, but not all, of the symptoms. The cause of Hanhart syndrome is not fully understood. Treatment depends on the signs and symptoms present in each person.

• Small mouth
• Short, incompletely developed tongue (hypoglossia)
• Absent, partially missing, or shortened fingers and/or toes
• Jaw abnormalities such as micrognathia, retrognathia (receding jaw), or partially missing mandible (lower jaw)
• High-arched, narrow, or cleft palate
• Absent or unusually formed arms and/or legs
• Missing teeth
• Absence of major salivary glands

Some infants with Hanhart syndrome may be born with paralysis of certain areas of the face. If the tongue and/or mouth are affected, this can worsen feeding difficulties that are already present due to the craniofacial abnormalities listed above.

The severity of the physical abnormalities associated with Hanhart syndrome varies greatly among affected people, and children with this disorder often have some, but not all, of the symptoms.

A diagnosis of Hanhart syndrome is typically made based on the presence of characteristic signs and symptoms. In some cases, the diagnosis may be suspected before birth if concerning features are seen on ultrasound.

Because Hanhart syndrome affects many different systems of the body, medical management is often provided by a team of doctors and other healthcare professionals. Treatment for this condition varies because it depends on the signs and symptoms present in each person. For example, limb and/or craniofacial abnormalities may be treated with surgery and/or prostheses. Affected children may also need speech therapy, physical therapy, and/or occupational therapy.

The long-term outlook (prognosis) for people with Hanhart syndrome varies and largely depends on the signs and symptoms present in each person. Severe associated craniofacial abnormalities can be life-threatening and may impair breathing, eating, and/or swallowing. However, early diagnosis and treatment can improve survival and quality of life for affected people.