Hanhart syndrome is one of the lesser-known conditions of our time, and there are minimal resources, which makes it quite difficult to navigate and understand its implications. At Klarity Health, we’re here to help you know Hanhart syndrome better and hopefully answer all your concerns. Let’s dive in.

What is hanhart syndrome?

Hanhart syndrome is a condition that affects the bottom half of the face and the lower limbs. It is a rare condition that is associated with many terms, such as Oromandibular limb hypoplasia syndrome, Hypo-glossia-hypodactylia syndrome, Peromelia with micrognathia or aglossia-adactylia syndrome- all these correspond to the changes in the structure of the lower face and limbs. But it should most definitely not be mistaken for Richner-Hanhart syndrome, which is an entirely different condition!

The exact reason for this condition is unknown;³ however, there have been speculations of a genetic component (specific information currently unavailable), as well as environmental influence and vascular problems during pregnancy, but it is mostly sporadic according to the literature. There have also been reports of certain drugs taken during pregnancy leading to babies being born with Hanhart syndrome, these drugs are not limited to Promethazine, Diazepam, Imipramine, and Trimethobenzamide hydrochloride.²

This condition affects both males and females alike, however, it is extremely rare, and there have been only an estimated of around 50 cases to date.

Usually, X-rays are used to determine limb irregularity. CT scans (a mode of imaging, similar to X-rays) can be used to determine any jaw deformities, but it is mostly diagnosed in a newborn baby by physical features and a full clinical assessment. Some features, such as full-forming facial expressions, absent teeth, difficulty speaking, and others, will be discovered much later as the child grows older.

Orthopaedic manifestations of hanhart syndrome

Orthopaedics is a branch of surgery that directly deals with bones, muscles, tendons, and ligaments.¹ The features that are associated with a child with Hanhart syndrome that may need surgical correction are:

• Small mouth
• Small or underdeveloped tongue
• Missing or smaller lower jaw
• Broad nose
• High-arched palate
• Increased distance between the eyelids
• Missing or underdeveloped fingers
• Missing or underdeveloped toes
• Tightness or rigidity of joints

Along with these, there may also be problems with the heart, kidneys, spleen, and the back passage. However, those features are addressed by other specialists and may not always need any surgical interventions.⁴

The importance of orthopaedic involvement in this condition is that allowing certain features to be altered surgically or non-surgically will greatly provide relief for the child. They may find it difficult to speak, breathe or swallow in some instances or in cases with limb problems, they may need the help of prosthetics or surgical correction to improve their natural mobility and reach their motor development milestones.

Orthopaedic contribution will also aid in their psycho-social outlook, lessen the burden of social pressures, and improve their childhood vastly. As this condition is quite a complex one, the exact treatment plan for children with this condition will be specific to them and will be discussed with a team of specialist doctors, such as paediatricians, speech and language therapists, geneticists, audiologists, surgeons, nutritionists, dentists, etc. The plan of any procedure or intervention will depend on the severity of the situation. It is difficult to say whether surgical attention will be lifelong or not as each case is unique. However, it is always early to start early. As children are constantly growing, their muscles and bones are constantly growing with them as well, It will be beneficial to the child to start young so that they recover faster and adapt better.

Non-surgical orthopaedic interventions

Non-surgical options can be used for people with mild forms of the disease, and those with limb deformities that can be aided with the use of physiotherapy and prosthetics. Prosthetics are available for most parts of the body and have proven to be a very effective remedy. Physiotherapy is a mode of physical therapy that helps regulate and improve one’s motor skills. When trained from a young age, the method becomes a habit and will improve their quality of life greatly. These proceedings will take place under expert advice from surgeons and physiotherapists who will provide guidance based on individual cases.

Surgical orthopaedic interventions

Surgical orthopaedic interventions can be done at any stage or age in life, however, it is recommended that it is done as early as possible while a child is actively developing their bones and muscles. The most important orthopaedic involvement in Hanhart syndrome is mending structures of the face. The bones, muscles, and joints of the face are important because they are primarily responsible for allowing a child to eat, breathe, speak, and swallow. They will recover faster when it is surgically mended at a young age. There may be a few challenges with anaesthetics (a drug used to put people to sleep during surgery so that the whole experience is painless), and there may have to be multiple operations rather than everything being done in one day.

Aside from surgery for the jaw, teeth, mouth and nose, the other common surgical attention in Hanhart syndrome would be for the limbs. This is usually if physiotherapy and prosthetics aren’t helpful, then surgeons may consider limb lengthening surgery and corrective surgery for joint contractures. There may also be involvement of the plastic surgeons.

After surgery, there will be post-operative monitoring and rehabilitation. This is done to keep track of the recovery stages and address any problems that need medical attention. Following a few days or weeks of recovery, there will be physiotherapy. In a long-term sense, there may be lifetime rehabilitation in some cases. Most report an apt recovery and a very smooth lifestyle.

Challenges and considerations in orthopaedic management

The criteria for surgery would mostly be if the condition is affecting the child’s well-being and way of life. Unnecessary surgery is looked down upon because although surgery is a great option, it also can come with certain complications that are associated with any surgery. According to research so far, people with this condition have recovered extremely well with surgery and physical therapy.

Considerations should be made in certain instances, if there is an absolute severity and other organs of the body are compromised, the medical team may decide to go with a non-surgical approach as surgery may be risky. In cases of Hanhart syndrome, there may be complications also associated with limited anatomy.

Parental support and patient-centred care are extremely important, people with Hanhart syndrome undergo a lot socially and psychologically so empathy and attention are invaluable.

If someone undergoes complex reconstructive type surgery, they will have to undergo long-term monitoring, so that doctors can keep up to date with their mobility. With modern technology and advancement, there will hopefully be more attention put on congenital conditions such as Hanhart syndrome. There is potential for gene therapy and regenerative medicine with the ongoing pace of research and discovery.

FAQs

What is hanhart syndrome?

It is a rare congenital condition that primarily affects the face and limbs (hands and legs).

Can you prevent hanhart syndrome?

The short answer is no; the recurrence of this condition is random, although certain connections have been made to environmental and maternal factors.

How do you treat hanhart syndrome?

There is no specific treatment plan, each individual case will be dealt with differently. The treatment team will include paediatricians, surgeons, rehabilitators, physiotherapists, nutritionists etc.

What are the orthopaedic interventions for hanhart syndrome?

The orthopaedic interventions can include surgery around the lower face and surgery of the hands and legs, This can include limb lengthening surgery, surgery to loosen rigid joints, and bone reconstruction of the jaw,  nose, and others. Physical therapy and monitoring after surgery may be lifelong.

Summary: Orthopaedic interventions in hanhart syndrome

Hanhart syndrome is a rare congenital disorder affecting the lower face and limbs, with around 50 documented cases. It presents with features like a small or missing jaw and tongue, underdeveloped fingers or toes, and joint rigidity. Its exact cause is unknown, though genetic, environmental, and drug-related factors during pregnancy may contribute.

Orthopaedic management plays a crucial role in improving mobility, function, and quality of life. Non-surgical interventions like physiotherapy and prosthetics are beneficial in mild cases. In more severe cases, surgical options such as jaw reconstruction, limb lengthening, and joint correction may be necessary, ideally performed early in life to align with growth and development.

Treatment plans are highly individualised and involve a multidisciplinary team. Challenges include the rarity of the condition, surgical risks, and anatomical limitations. However, with early intervention and comprehensive care, children can experience improved physical and psychosocial outcomes.