The Rett Syndrome Association of Ireland

About CDKL5

CDKL5 is the name of a gene on the X Chromosome. It’s also the name used for a very rare condition that results from abnormalities on this gene. This condition is described as early onset, with difficult to control seizures and neurodevelopmental impairment. The condition is more common in girls than boys, so much so that it is often described as ‘usually affecting girls’.

At time of writing, there are little more than 200 diagnosed cases worldwide. However, we can expect more children to be diagnosed as awareness of CDKL5 spreads. Diagnosis is by genetic test on a blood sample.

Symptoms include some of the following of this general list – not everyone affected with CDKL5 will have all of these, and there may be other issues too.

  • Epileptic seizures – early onset in the first 5 or so months. The Seizures can take many forms including myoclonic jerks
  • Infantile Spasms
  • Microcephaly (smaller than usual head size)
  • Hand wringing and mouthing
  • Marked developmental delay
  • Limited or no speech
  • Hypersensitivity to touch
  • Lack of, or poor, eye contact
  • Gastro-oesophageal reflux
  • Small feet, cold feet
  • Breathing irregularities
  • Teeth grinding
  • Poor muscle tone
  • Limited hand skills
  • Crying or Laughing episodes with no cause
  • Some autistic-like tendencies

Epilepsy is very common, almost everyone will be affected. It typically starts at a very early age – 3 months is common. Seizures can come in different forms: Star-Shaped fits, Choking-like episodes, rigidity and stiffness for a short period, unusual facial grimacing and so on. Seizures can occur on a daily basis and can build up over time in number, duration and severity. Infantile Spasms can occur and these can also resolve over time. In some cases people have been seizure-free for periods from six weeks to nine months. These periods have been observed in girls between 12 and 24 months old.

CDKL5 is described as early onset, with difficult to control seizures and neurodevelopmental impairment

Treatment with drugs has mixed results. With new medication everyone seems to have a honeymoon period, but once this period passes there can be changes to the type of seizure or increases in severity. Major seizures, including complex partial seizures and grand mal seizures, extended in duration, can be experienced regularly until adulthood. Brief seizures such as absence, drop fits, and myoclonic jerks can occur on a daily basis. Most people with CDKL5 develop myoclonic jerks as part of their seizures, some people also describe episodes of status epilepticus – both convulsive and non-convulsive.

Developmental skills may be lost with severe seizure disorder.

As very few adults have been diagnosed with CDKL5 it’s difficult to speak with any certainty about the seizure disorder in older people. However, present indications suggests that seizures are at their worst in childhood and may get worse during puberty. (Some girls have benefitted from injectable contraceptives to manage monthly variation in seizures.) There are indications that the seizure condition may improve in adulthood, although small brief seizures may persist, particularly myoclonic jerks.

Unfortunately at this time there is no medication known to particularly beneficial to people with CDKL5, though some have seen some improvement with Topomax.

This article is prepared with the assistance of a leaflet published by Rett UK and other sources on the Internet. It’s published here for information purposes only. Medical advice should be sought from a Medical Professional.