Tetrasomy 18p

Tetrasomy 18p is a rare chromosomal disorder in which there are four copies (tetrasomy) of the short arm of chromosome 18 (18p) instead of the usual two. The disorder is characterized by developmental delay, intellectual disability, and distinctive facial features.

Signs and Symptoms

Individuals with Tetrasomy 18p often have developmental delay and intellectual disability, which can range from mild to severe. They may also have distinctive facial features, such as a high forehead, a short nose with a broad tip, widely spaced eyes (hypertelorism), and a thin upper lip. Other features can include short stature, heart defects, hearing loss, and urogenital abnormalities.

Causes

Tetrasomy 18p is caused by a random error during the formation of reproductive cells (eggs or sperm) or in early fetal development. Affected individuals have four copies of the short arm of chromosome 18 instead of the usual two. This extra genetic material disrupts the normal course of development, leading to the characteristic features of the disorder.

Diagnosis

The diagnosis of Tetrasomy 18p is usually made by a genetic test called a chromosomal analysis or karyotype. This test can identify the extra copy of chromosome 18p.

Treatment

There is no cure for Tetrasomy 18p, but treatment can help manage the symptoms. This may include physical therapy, occupational therapy, and speech therapy to help with developmental delays. Surgery may be needed for heart defects or other physical abnormalities.

See Also

• Chromosome 18
• Genetic Disorders
• Developmental Delay
• Intellectual Disability

References

Tetrasomy 18p Resources
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