1q21.1 deletion syndrome

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
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1q21.1 deletion syndrome
Synonyms	1q21.1 microdeletion syndrome
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Specialty	Medical genetics
Symptoms	Developmental delay, intellectual disability, congenital heart defects, schizophrenia, autism spectrum disorder
Complications	N/A
Onset	Congenital
Duration	Lifelong
Types	N/A
Causes	Genetic mutation
Risks
Diagnosis	Genetic testing, chromosomal microarray analysis
Differential diagnosis	1q21.1 duplication syndrome, other chromosomal abnormalities
Prevention
Treatment	Supportive care, special education, therapy
Medication
Prognosis	Variable
Frequency	1 in 5,000 to 1 in 10,000
Deaths

1q21.1 deletion syndrome is a rare genetic disorder caused by a deletion of a small segment of chromosome 1. This deletion occurs at the q21.1 region, which is located on the long arm of the chromosome. The syndrome is associated with a variety of clinical features, which can vary widely among affected individuals.

Genetic Basis

The 1q21.1 deletion involves the loss of a segment of DNA that contains several genes. The size of the deletion can vary, but it typically spans approximately 1.35 megabases. This region includes several important genes, such as GJA5, CHD1L, and BCL9. The deletion can occur de novo or be inherited from a parent who carries the deletion but may not show any symptoms.

Clinical Features

Individuals with 1q21.1 deletion syndrome may exhibit a range of symptoms, including:

• Developmental delay
• Intellectual disability
• Autism spectrum disorder
• Congenital heart defects
• Microcephaly
• Seizures

The severity of these symptoms can vary significantly, even among members of the same family.

Diagnosis

Diagnosis of 1q21.1 deletion syndrome is typically made using genetic testing methods such as chromosomal microarray analysis or fluorescence in situ hybridization (FISH). These tests can identify the presence of the deletion and help in understanding the genetic basis of the individual's symptoms.

Management

There is no cure for 1q21.1 deletion syndrome, and treatment is focused on managing the symptoms. This may include:

• Speech therapy and occupational therapy for developmental delays
• Special education services
• Medications to control seizures
• Surgical interventions for congenital heart defects

See Also

• Chromosome 1
• Genetic disorder
• Chromosomal microarray
• Autism spectrum disorder