Hanhart syndrome

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.^[1][2][3]

The signs and symptoms of Hanhart syndrome vary, but may include:^[3][4][1]

• 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.^[3]

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.

Although there is no list of experts for rare diseases, a fact sheet is available on our Web site with tips for finding healthcare professionals and researchers who have experience with a particular condition. Potential resources include patient advocacy groups, researchers conducting clinical trials, and authors of articles published in medical journals. Click here to view our fact sheet. If you are unable to locate an expert using these suggestions, please let us know.