Rhizomelic Chondrodysplasia Punctata (RCDP)

Callie has RCDP
Callie has RCDP

RCDP is a genetic disorder which is a form of dwarfism.

‘Rhizomelic’ means shortening of the bones closest to the body’s trunk.

‘Chondrodysplasia’ refers to malformation (the dysplasia part of the word) of the cartilage (the chondro part of the word). ‘Punctata’ refers to an unusual stippling on the end of the bones that join the shoulders and elbows (the humerus) and the top of the leg and the hip (femur). On X-ray an infant’s bones look spotty at the ends.

A child with RCDP will have low levels of ‘plasmalogens’, molecules required for the body to function properly. This is how doctors determine the prognosis for the child - a blood test for plasmalogens. The higher the plasmalogen levels the better the outcome for the child. Once a child has been diagnosed with RCDP a skin sample is taken to determine which type of RCDP a child has (see below).

An RCDP infant will often, but not always, be born with cataracts in both eyes. They might suffer stiff joints and dry skin. Other visual clues to RCDP are a small, up-turned nose, low-set ears and an unusually small head circumference.

If RCDP is not picked up in baby scans it might first present itself when an infant is described by health visitors or GPs as ‘failing to thrive’ i.e. not growing as they should. This inability to grow is not down to nutrition but part of the condition.

RCDP sufferers have severe learning difficulties. The condition can be life-limiting at an early age.

RCDP is classed as ‘peroxisomal’ disorder. ‘Peroxisomes’ are little structures within cells whose function is to break down chemical and convert them to forms the body can use. Because the peroxisomes in RCDP sufferers aren’t working properly there is a build-up of chemicals normally broken down.

It is not yet known exactly how those build-ups cause the problems associated with RCDP.

There are 44 children across the world known to Rhizo Kids, the international support organisation. Occurance is thought to be one in 100,000 chidren.

RCDP can manifest itself in three types. RCDP Type 1 is the most prominent. Children have two defects - low plasmalogen levels and an inability to break down phytanic acid (see below).
Type 2 and 3 have only one defect - low plasmalogen levels.

Within all three types a child can be severe or mild. It depends on their plasmalogen levels.
Remember, each child is different.

Contact other families affected by rhizomelic chondrodysplasia punctata

Treatments

There is no cure for RCDP however research is being carried out in the United States into potential treatments.

Doctors and therapists can help manage the symptoms of RCDP.

It is important a child has the level of ‘phytanic acid’ in their blood measured. If the result is unusually high the child should follow a low-fat diet. Phytanic acids are found in high-fat dairy products and oily fish.

Nutritionists will suggest alternatives and should come up with the best possible diet for RCDP children.

Breathing issues are common in children with RCDP. Respiratory infections such aspneumonia, and aspiration (inhaling liquids or solids into the lungs) may affect sufferers. Some children have heart defects.

Cataracts can be removed in infancy through surgery.

Physiotherapists and occupational therapists can help relieve the symptoms of a child’s unusual skeletal development such as ‘scoliosis’ (side to side curvature) of the spine and joint stiffness.

Many children with severe RCDP will never be able to sit unsupported. Physios and OTs can suggest equipment that will help a child live as full and comfortable a life as possible.

Some sufferers have a tendency to overheat even when it is cold. Temperature should be monitored, sheets can be provided that moderate temperature while a child is sleeping.

Genetics and inheritance

RCDP is caused by a defect in the Pex7 gene. The condition is ‘autosomal recessive’ (in 99.9% of cases) so both parents have the defective gene.

Thereis a one in four chance a sibling of an RCDP sufferer will have the disorder too. There is a 50 per cent chance of a sibling being an unaffected carrier of the abnormal Pex7 gene.

RCDP is classed as a ‘peroxisomal’ disorder. ‘Peroxisomes’ are little structures within cells whose function is to break down chemical and convert them to forms the body can use. Because the peroxisomes in RCDP sufferers aren’t working properly there is a build-up of chemicals normally broken down.

It is not yet known exactly how those build-ups cause the problems associated with RCDP.

Contact other families affected by rhizomelic chondrodysplasia punctata

We will try to put you in touch with other families affected by rhizomelic chondrodysplasia punctata. Fill in the form below and a member of our support team will get back to you within 7 working days.

About you
Your message
Share this page

Welcome to the GDUK network

If this is the first time you have searched for information on a particular condition, details you find here may be distressing.

» If you would rather read our Newly Diagnosed section for parents and carers first click here