18p-

Genetic disorder involving deletion of part of chromosome 18

18p- is a genetic disorder caused by the deletion of all or part of the short arm (p arm) of chromosome 18. This condition is one of the many chromosomal deletion syndromes and can lead to a variety of developmental and physical abnormalities.

Genetics

Cebocephaly, a possible feature of 18p-

The human genome consists of 23 pairs of chromosomes, each containing a long arm (q arm) and a short arm (p arm). In individuals with 18p-, there is a deletion of genetic material from the short arm of chromosome 18. The size of the deletion can vary, and the specific genes lost in the deletion determine the severity and range of symptoms.

The deletion can occur de novo, meaning it is a new mutation that arises in the individual, or it can be inherited from a parent who carries a balanced chromosomal translocation.

Symptoms

The symptoms of 18p- can vary widely among affected individuals, depending on the size and location of the deletion. Common features include:

• Developmental delay and intellectual disability
• Hypotonia (low muscle tone)
• Distinctive facial features, such as a flat nasal bridge and epicanthal folds
• Hearing loss
• Growth retardation
• Cebocephaly, a rare craniofacial anomaly

Diagnosis

Diagnosis of 18p- is typically made through genetic testing, such as karyotyping or chromosomal microarray analysis. These tests can identify the deletion on chromosome 18 and help determine its size and the specific genes involved.

Management

There is no cure for 18p-, but management focuses on addressing the symptoms and improving quality of life. This may include:

• Early intervention programs to address developmental delays
• Speech therapy, occupational therapy, and physical therapy
• Regular monitoring of growth and development
• Hearing assessments and interventions if necessary

Prognosis

The prognosis for individuals with 18p- varies depending on the severity of the symptoms and the presence of any associated health issues. With appropriate support and interventions, many individuals can lead fulfilling lives.

Related pages

• Chromosomal deletion syndrome
• Chromosome 18
• Genetic disorder