Multiple epiphyseal dysplasia

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Multiple epiphyseal dysplasia is a disorder of cartilage and bone development primarily affecting the ends of the long bones in the arms and legs (epiphyses). There are two types of multiple epiphyseal dysplasia, which can be distinguished by their pattern of inheritance. Both the dominant and recessive types have relatively mild signs and symptoms, including joint pain that most commonly affects the hips and knees, early-onset arthritis, and a waddling walk. Although some people with multiple epiphyseal dysplasia have mild short stature as adults, most are of normal height. The majority of individuals are diagnosed during childhood; however, some mild cases may not be diagnosed until adulthood.

Recessive multiple epiphyseal dysplasia is distinguished from the dominant type by malformations of the hands, feet, and knees and abnormal curvature of the spine (scoliosis). About 50 percent of individuals with recessive multiple epiphyseal dysplasia are born with at least one abnormal feature, including an inward- and upward-turning foot (clubfoot), an opening in the roof of the mouth (cleft palate), an unusual curving of the fingers or toes (clinodactyly), or ear swelling. An abnormality of the kneecap called a double-layered patella is also relatively common.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in the COMP, COL9A1, COL9A2, COL9A3, or MATN3 gene can cause dominant multiple epiphyseal dysplasia. These genes provide instructions for making proteins that are found in the spaces between cartilage-forming cells (chondrocytes). These proteins interact with each other and play an important role in cartilage and bone formation. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears.

The majority of individuals with dominant multiple epiphyseal dysplasia have mutations in the COMP gene. About 10 percent of affected individuals have mutations in the MATN3 gene. Mutations in the COMP or MATN3 gene prevent the release of the proteins produced from these genes into the spaces between the chondrocytes. The absence of these proteins leads to the formation of abnormal cartilage, which can cause the skeletal problems characteristic of dominant multiple epiphyseal dysplasia.

The COL9A1, COL9A2, and COL9A3 genes provide instructions for making a protein called type IX collagen. Collagens are a family of proteins that strengthen and support connective tissues, such as skin, bone, cartilage, tendons, and ligaments. Mutations in the COL9A1, COL9A2, or COL9A3 gene are found in less than five percent of individuals with dominant multiple epiphyseal dysplasia. It is not known how mutations in these genes cause the signs and symptoms of this disorder. Research suggests that mutations in these genes may cause type IX collagen to accumulate inside the cell or interact abnormally with other cartilage components.

Some people with dominant multiple epiphyseal dysplasia do not have a mutation in the COMP, COL9A1, COL9A2, COL9A3, or MATN3 gene. In these cases, the cause of the condition is unknown.

Mutations in the SLC26A2 gene cause recessive multiple epiphyseal dysplasia. This gene provides instructions for making a protein that is essential for the normal development of cartilage and for its conversion to bone. Mutations in the SLC26A2 gene alter the structure of developing cartilage, preventing bones from forming properly and resulting in the skeletal problems characteristic of recessive multiple epiphyseal dysplasia.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Multiple epiphyseal dysplasia can have different inheritance patterns.

This condition can be inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

Multiple epiphyseal dysplasia can also be inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

The incidence of dominant multiple epiphyseal dysplasia is estimated to be at least 1 in 10,000 newborns. The incidence of recessive multiple epiphyseal dysplasia is unknown. Both forms of this disorder may actually be more common because some people with mild symptoms are never diagnosed.

Which doctor should you see?

The suggested department for discussing Multiple epiphyseal dysplasia is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Multiple epiphyseal dysplasia. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.