What is CDKL5 Deficiency Disorder (CDD)?

CDKL5 Deficiency Disorder (called CDD for short) is a rare condition that affects the brain and the body. It happens because of a change in a special set of instructions inside the body, called a gene, that helps the brain grow and work properly.

Because of this change, children with CDD might have trouble learning new things, moving their bodies the way they want, or talking. Many also have seizures, which are like sudden ‘storms’ in the brain that can make their bodies shake or stop moving for a little while.

Even thought CDD makes some things harder, children with the condition can still learn, play, and share love in their own special ways. Doctors, therapists, and families work together to help them be as happy and healthy as possible.

More about CDD

CDKL5 Deficiency Disorder (CDD) is a rare X-linked genetic condition that causes early-onset seizures and mild to severe delay in brain development.

CDD is classed as a rare condition, however more and more children and adults are being diagnosed every day. Every person with CDD is unique, and the condition affects each person in a different way. Symptoms can vary from mild to severe.

Most children affected by CDD experience seizures that begin in the first few months of life. These seizures can be difficult to control using the medicines that are currently available via the NHS. However, some children and adults experience mild or well-controlled seizures, and some do not experience seizures at all.

Most people with CDD cannot walk, talk, or feed themselves, and many use wheelchairs and are dependent on their parents or carers for most day-to-day activities. Many people experience scoliosis (twisting of the spine), problems with their vision, sensory issues and sensitivity, and various gastrointestinal difficulties.

As time has gone on it appears that there might be other symptoms that play a role in the condition, and below you can find a list of some of the most commonly-associated ones.

  • Epileptic seizures starting in the first 8 months of life
  • Infantile spasms (in about 50%)
  • Many different types of epilepsy usually including myoclonic jerks
  • Hand stereotypies in the form of hand clapping, tapping, movements or mouthing
  • Marked developmental delay
  • Limited or absent speech
  • Hypersensitivity to touch, for example dislike of hair brushing
  • Lack of eye contact or poor eye contact, but may have intensive eye interaction
  • Gastroesophageal reflux, and other severe gastrointestinal problems such as low gut motility
  • Constipation
  • Small, cold feet
  • Breathing irregularities such as hyperventilation
  • Grinding of the teeth
  • Episodes of laughing or crying for what appears to be no reason
  • Low/Poor muscle tone
  • Very limited hand skills
  • Some autistic‐like tendencies
  • Scoliosis
  • Cortical Visual Impairment (CVI), aka “cortical blindness”
  • Apraxia
  • Eating/drinking challenges, such as refusal to eat and drink, as well as giving up altogether
  • Interrupted sleep
  • Characteristics such as a sideways glance, and habit of crossing legs

 

It is important to remember that every person with CDD is unique, and each person will experience different symptoms, of varying severity.

A brief summary of the science behind the condition

The CDKL5 gene provides instructions for making a protein that is essential for normal brain development. Although little is known about the protein’s function, it may play a role in regulating the activity of other genes, including the MECP2 gene (or Rett Syndrome).

The CDKL5 protein acts as a kinase, which is an enzyme that changes the activity of other proteins by adding oxygen and phosphate atoms (a phosphate group) at specific positions. Researchers have not yet determined which proteins are targeted by the CDKL5 protein.

More about the Genetics of CDD