what Is Haim-Munk Syndrome

Introduction

Haim-Munk (HM) syndrome, also known as Cochin-Jewish disorder due to it first being reported in Jewish families in Cochin, India, is an extremely rare genetic disease. HM syndrome is the result of a child inheriting two copies of a defective gene, specifically the lysosomal protease cathepsin C gene, from their parents. The lysosomal protease cathepsin C gene is located on chromosome 11 and encodes a protein involved in protein degradation and metabolism.^3,5,6 

HM syndrome is typically present at birth and is characterised by abnormalities of the skin, nails, and gums. Doctors can diagnose HM syndrome, but must be careful to distinguish it from Papillon-Lefevre syndrome, which has similar symptoms.⁷ The symptoms of HM syndrome can vary across patients, and therefore, management and treatment can vary too. However, treatment will often involve a team of various medical specialists, such as general physicians, paediatricians, surgeons, dermatologists, and dentists.^1,2,3

Causes of haim-munk syndrome

HM syndrome is the result of a child inheriting two defective copies of the lysosomal protease cathepsin C gene from their parents.  HM syndrome is an autosomal recessive condition; this means that both of a child’s parents have to pass on a copy of the defective gene for their child to be affected. A child with two parents carrying the defective gene will have a 50% chance of also carrying the defective gene and a 25% chance of having HM syndrome. As is the case for all autosomal recessive conditions, someone must inherit two copies of the defective gene in order to have the condition.^1,2

Although there have not been many cases of HM syndrome reported, the condition has been linked to children with parents who are closely related by blood. Therefore, children in these circumstances may be more likely to have HM syndrome.^3,5,6

Signs and symptoms of Haim-Munk syndrome

HM syndrome can affect patients in a range of ways, but it primarily affects the skin, nails, and gums. Common symptoms include:

• Palmoplantar hyperkeratosis: Patients may have dry scaly patches of skin on the palms of their hands and soles of their feet. These patches may be present at birth or appear as late as five years of age. They can be confined to the hands or feet or spread to the elbows or knees and, rarely, to the face
• Gum inflammation: Whilst the teeth of HM syndrome patients typically develop normally, the gums often become inflamed –  a condition known as gingivitis. This inflammation may present as an infant’s baby teeth come through and can cause bleeding. This inflammation may cause the gums to become weak, making it difficult for the teeth to be held in place and typically causing the teeth to fall out by the age of 16⁵
• Overgrowth of fingernails and toenails: The fingernails and toenails of patients with HM syndrome may grow rapidly, causing them to appear thick and making them curve inwards, resulting in them looking similar to a hook
• Deformity of the hands and feet: Patients with HM syndrome may have abnormally long and slender fingers and toes. Sometimes, the bones at the ends of the fingers and toes may become frail and degenerate. In addition, patients may have flat feet – a condition known medically as pes planus
• Numbness: As a result of a lack of blood flow to the fingers and toes, patients with HM syndrome may feel numbness in these areas, particularly when they are exposed to cold temperatures³

Diagnosis of Haim-Munk syndrome

HM syndrome is typically diagnosed by a doctor after observing a patient’s condition.  Sometimes, doctors may also use X-rays to view physical deformities. As HM syndrome can look similar to other conditions, it is important that your doctor rules these out when examining you.³ 

Similar conditions include:

Physical examination

A doctor will be able to observe some deformities in the newborn that are indicative of HM syndrome. However, some symptoms of HM syndrome can take years to present, and so observations may need to take place over a number of years to confirm a diagnosis.³

X-rays

X-rays can be used to detect certain abnormalities that may be present in patients with HM syndrome, which include abnormalities of the teeth, elongated fingers and toes, and flat feet.^1,3

X-rays are quick and pain-free procedures. They use radiation, which is passed through the body, to help create an image in which the bones can be viewed easily. A doctor will then examine these images to identify any issues or abnormalities.

Management and treatment of Haim-Munk syndrome

The management and treatment of HM syndrome are tailored to each patient's signs and symptoms. As HM syndrome can affect a range of bodily systems, various medical specialists may collaborate in caring for patients, such as general physicians, paediatricians, surgeons, dermatologists, and dentists. Although HM syndrome typically requires a tailored care plan, several modes of management and treatment have featured in successful plans for patients with HM syndrome:

• Skin grafts: This is a surgical procedure used to replace damaged skin with healthy skin. There are different types of skin grafts, classified according to where the skin is sourced from. A plastic surgeon performs a skin graft and can be consulted to determine whether a skin graft would be suitable for you and what type may be best suited for your condition 
• Protective clothing: Wearing protective clothing can help patients cope with increased sensitivity to the cold, helping them to avoid numbness
• Shoes designed for flat feet: Wide shoes with a low heel or with insoles inside the shoes can serve as more suitable footwear for patients with flat feet, making moving easier and more comfortable 
• Oral retinoids: Oral retinoids, such as acitretin, etretinate, and isotretinoin, can help alleviate problems with the skin and gums. However, sometimes, oral retinoids can cause side effects, which include dry mouth, dry skin, itching, body aches, and headaches
• Genetic counselling: Having HM syndrome means that you have a higher chance of also having a child with HM syndrome. Genetic counselling can help you be more aware of any risks and make more informed decisions when thinking of having a child³

FAQs

How common is Haim-Munk syndrome?

HM syndrome is extremely rare, but how rare isn’t exactly known. It seems to be more common in the children of close-blood parents. The condition appears to be equally common in people assigned male at birth and people assigned female at birth.^1,3

What is the outlook like for those with Haim-Munk syndrome?

The signs and symptoms of HM syndrome can be difficult to deal with but generally aren’t life-threatening. With appropriate management and treatment, they can be alleviated.³

Can Haim-Munk syndrome be cured?

HM syndrome cannot be cured, but management and treatment can help alleviate its signs and symptoms. This typically requires a team of different medical specialists and can involve medication, surgery, and lifestyle adjustments.³

Summary

HM syndrome is an extremely rare genetic disorder that causes abnormalities of the skin, nails, and gums. The signs and symptoms of HM syndrome may be present at birth or take several years to become apparent. The condition can present similarly to other disorders (particularly Papillon-Lefevre syndrome), so these must be ruled out when establishing a diagnosis. A diagnosis can be made through a doctor observing a patient’s signs and symptoms and ruling out other conditions. 

Since the signs and symptoms of HM syndrome can vary, each patient will most likely require a customised treatment plan. This will typically involve a range of medical specialists, due to the multiple bodily systems that the condition affects, and can involve medication, surgery, and lifestyle adjustments, such as specialised clothing.

Genetic counselling can help patients make more informed decisions when deciding whether to have children in situations of their increased risk of having a child with HM syndrome.