How do I know if I have Pallister-Killian Syndrome / Tetrasomy 12p?

Pallister-Killian Syndrome (PKS), also known as Tetrasomy 12p, is a rare genetic disorder caused by the presence of extra genetic material on the short arm of chromosome 12. It is characterized by a wide range of physical and developmental abnormalities. Diagnosing PKS can be challenging due to its rarity and the variability of symptoms among affected individuals.

Physical Features: Individuals with PKS may exhibit distinct physical characteristics, although these can vary widely. Some common features include a high forehead, widely spaced eyes, a flat nasal bridge, low-set ears, a short neck, and a small mouth. Additionally, individuals may have abnormalities in their hands and feet, such as extra fingers or toes, or unusually shaped nails.

Developmental Delays: Developmental delays are a hallmark of PKS. Infants with PKS may have low muscle tone (hypotonia) and experience delays in reaching developmental milestones such as sitting, crawling, and walking. Intellectual disability is also common, ranging from mild to severe. Speech and language delays are often observed, and individuals may have difficulty with expressive and receptive communication.

Medical Issues: PKS can be associated with various medical problems. Seizures are relatively common, and individuals may require medication to manage them. Vision and hearing impairments can also occur. Additionally, individuals with PKS may have heart defects, kidney abnormalities, gastrointestinal issues, and respiratory problems.

Genetic Testing: The definitive diagnosis of PKS is made through genetic testing, specifically a chromosome analysis called a karyotype. This test examines the structure and number of chromosomes in a person's cells. In PKS, the karyotype typically reveals the presence of four copies (tetrasomy) of the short arm of chromosome 12.

Consultation with Specialists: If you suspect you or your child may have PKS, it is important to consult with a medical geneticist or a genetic counselor. They can evaluate the individual's symptoms, review their medical history, and order appropriate genetic testing. These specialists can also provide guidance and support for managing the condition and connecting with support networks.

Conclusion: Pallister-Killian Syndrome, or Tetrasomy 12p, is a rare genetic disorder characterized by physical features, developmental delays, and potential medical issues. Genetic testing, specifically a karyotype, is necessary for a definitive diagnosis. If you suspect PKS, it is crucial to consult with a medical geneticist or genetic counselor for proper evaluation and guidance.