STK9/CDKL5 (cyclin-dependent kinase-like 5)

STK9/CDKL5 (cyclin-dependent kinase-like 5) Gene Mutation Analysis

Atypical Rett
West syndrome (Infantile spasms)
X-linked Mental Retardation

Rett syndrome is an X-linked dominant, progressive neurological disorder that primarily affects females, due to the lethality of severe mutations in males. It is characterized by normal development early on in life, followed by an arrest in development, and subsequently, a regression in language and motor skills. Most individuals typically develop loss of purposeful hand movements, and instead develop stereotypical repetitive hand motions. Approximately 50% of these individuals will also develop seizures, including infantile spasms. Rett syndrome may present in its “classic form”, usually associated with mutations in the MECP2 gene. It may also be classified as “atypical” Rett syndrome, considered to be a milder form of this disease with clinical features including mental retardation, mild learning disabilities and/or autism. Many different syndromes have been described where much overlap occurs between the clinical presentations, making it difficult to place some individuals in a particular diagnostic box. A number of recent publications have reported associations of mutations in the STK9/CDKL5 gene, which a protein containing a conserved serine/threonine kinase domain, with phenotypic presentations ranging from severe mental retardation with infantile spasms to variable neurodevelopmental disorders with overlapping symptoms found in Rett and Angelman syndrome 1, 2, 3.

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STK9/CDKL5 Gene Mutation Analysis Assay Summary
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  1. Kalscheuer VM et al. Am J Hum Genet. 2003 Jun;72(6):1401-11.
  2. Tao J et al. Am J Hum Genet. 2004 Dec;75(6):1149-54.
  3. Scala E et al. J Med Genet. 2005 Feb;42(2):103-7.