Hanhart syndrome

Not to be confused with Richner-Hanhart syndrome.

Alternate names

Aglossia adactylia; Hypoglossia-hypodactylia syndrome; Peromelia with micrognathia

Definition

Hanhart syndrome is a rare condition that primarily affects the craniofacial region and the limbs (arms and legs).

Cause

The exact underlying cause of Hanhart syndrome is currently unknown. However, researchers suspect that there may be genetic and/or environmental factors that contribute to the development of the condition. To date, no specific disease-causing genes have been identified. Possible environmental factors including:

• Exposure of the pregnant mother to radiation, teratogenic medications, or hypothermia
• Trauma or disrupted blood flow to the baby in the womb
• Chorionic villus sampling procedures (when performed too early in the pregnancy)

Signs and symptoms

The signs and symptoms of Hanhart syndrome vary, but may include:

• 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.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Aplasia/Hypoplasia of the tongue
• Hypoplasia of the zygomatic bone(Cheekbone underdevelopment)
• Micrognathia(Little lower jaw)
• Narrow mouth(Small mouth)
• Upper limb phocomelia

30%-79% of people have these symptoms

• Abnormal fingernail morphology(Abnormal fingernails)
• Adactyly
• Brachydactyly(Short fingers or toes)
• Cleft palate(Cleft roof of mouth)
• Finger syndactyly
• Hypodontia(Failure of development of between one and six teeth)
• Short distal phalanx of finger(Short outermost finger bone)
• Split hand(Claw hand)
• Telecanthus(Corners of eye widely separated)
• Wide nasal bridge(Broad nasal bridge)

5%-29% of people have these symptoms

• Abnormal cranial nerve morphology
• Anal atresia(Absent anus)
• Death in infancy(Infantile death)
• Facial asymmetry(Asymmetry of face)
• Feeding difficulties in infancy
• Gastroschisis
• High palate(Elevated palate)
• Intellectual disability(Mental deficiency)
• Jejunal atresia
• Neurological speech impairment(Speech disorder)

Diagnosis

• 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.

Treatment

• 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.

Prognosis

• 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.

NIH genetic and rare disease info

• NIH info on Hanhart syndrome

Hanhart syndrome is a rare disease.

Hanhart syndrome Resources
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