How is Pallister-Killian Syndrome / Tetrasomy 12p diagnosed?

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. This condition is characterized by a wide range of physical and developmental abnormalities. Diagnosing PKS involves a combination of clinical evaluation, genetic testing, and laboratory analysis.

Clinical Evaluation:

Diagnosing PKS typically begins with a thorough clinical evaluation by a healthcare professional. The doctor will assess the individual's medical history, conduct a physical examination, and look for characteristic signs and symptoms associated with PKS. These may include:

• Distinctive facial features such as a high forehead, widely spaced eyes, and a flat nasal bridge


• Hypotonia (low muscle tone) and developmental delays


• Intellectual disability and learning difficulties


• Seizures


• Abnormalities in the skeletal system, such as extra fingers or toes


• Heart defects

Genetic Testing:

Genetic testing plays a crucial role in confirming the diagnosis of PKS. The most common method used is a chromosomal microarray analysis (CMA). This test examines the individual's chromosomes at a high resolution, allowing for the detection of small genetic changes. In PKS, the CMA may reveal the presence of extra genetic material on the short arm of chromosome 12.

Laboratory Analysis:

In addition to genetic testing, laboratory analysis can provide further confirmation of PKS. A skin biopsy may be performed to examine the individual's cells under a microscope. This can reveal the presence of extra genetic material on chromosome 12 in the cells. The laboratory analysis may also include a karyotype analysis, which examines the structure and number of chromosomes in the cells.

Other Diagnostic Tools:

While clinical evaluation, genetic testing, and laboratory analysis are the primary methods of diagnosing PKS, other diagnostic tools may be used to assess specific symptoms or complications associated with the condition. These may include:

• Electroencephalogram (EEG) to detect abnormal brain activity in individuals with seizures


• Echocardiogram to evaluate heart function and detect any cardiac abnormalities


• Developmental assessments to evaluate cognitive and motor skills


• Imaging studies, such as X-rays or magnetic resonance imaging (MRI), to assess skeletal abnormalities or other structural defects

Conclusion:

Diagnosing Pallister-Killian Syndrome / Tetrasomy 12p involves a comprehensive approach that combines clinical evaluation, genetic testing, and laboratory analysis. The distinctive signs and symptoms associated with PKS, along with the presence of extra genetic material on chromosome 12 detected through genetic testing and laboratory analysis, help confirm the diagnosis. It is important for individuals suspected of having PKS to undergo a thorough evaluation by healthcare professionals experienced in diagnosing and managing rare genetic disorders.