CDKL5 deficiency disorder - Genetics Home Reference

CDKL5 deficiency disorder - Genetics Home Reference

CDKL5 deficiency disorder is characterized by seizures that begin in infancy, followed by significant delays in many aspects of development.

Seizures in CDKL5 deficiency disorder usually begin within the first 3 months of life, and they can appear as early as the first week after birth. The types of seizures change with age, and they usually follow a predictable pattern. Seizures occur daily in most affected individuals, and they are resistant to treatment.

Development is impaired in children with CDKL5 deficiency disorder. Most have severe intellectual disability and little or no speech. The development of gross motor skills, such as sitting, standing, and walking, is delayed. About one-third of affected individuals are able to walk independently. Fine motor skills, such as picking up small objects with the fingers, are also impaired; about half of affected individuals have purposeful use of their hands.

Other common features of CDKL5 deficiency disorder include repetitive hand movements (stereotypies), such as clapping, hand licking, and hand sucking; tooth grinding (bruxism); disrupted sleep; feeding difficulties; and gastrointestinal problems including constipation and backflow of acidic stomach contents into the esophagus (gastroesophageal reflux). Some affected individuals have episodes of irregular breathing. Distinctive facial features in some people with CDKL5 deficiency disorder include a high and broad forehead, large and deep-set eyes, a well-defined space between the nose and upper lip (philtrum), full lips, widely spaced teeth, and a high roof of the mouth (palate). Other physical differences can also occur, such as an unusually small head size (microcephaly), side-to-side curvature of the spine (scoliosis), and tapered fingers.

About 90 percent of people diagnosed with CDKL5 deficiency disorder are female. Affected males tend to have more severe developmental disabilities, including profound intellectual disability and almost no development of gross and fine motor skills.

CDKL5 deficiency disorder was previously classified as an atypical form of Rett syndrome. These conditions have overlapping features, including seizures, intellectual disability, and other problems with development. However, the signs and symptoms associated with CDKL5 deficiency disorderand its genetic cause are distinct from those of Rett syndrome, and CDKL5 deficiency disorder is now considered a separate condition.