HUNTINGTON DISEASE - MUTATION ANALYSIS CAG REPEATS

Huntington Disease - Mutation Analysis CAG Repeats is an advanced molecular genetic test used to detect and measure CAG trinucleotide repeat expansions in the HTT (Huntingtin) gene. Expansion of these CAG repeats is the genetic cause of Huntington disease, a progressive inherited neurodegenerative disorder that affects movement, cognition, and behavior.

The test accurately determines the number of CAG repeats present in the HTT gene and helps confirm a diagnosis of Huntington disease, evaluate individuals with suggestive symptoms, and assess genetic risk in family members. Molecular analysis of CAG repeat expansion is considered the gold standard for diagnosing Huntington disease.

Benefits of the Test

• Accurately detects HTT gene CAG repeat expansions.
• Confirms the genetic diagnosis of Huntington disease.
• Helps evaluate individuals with suggestive neurological symptoms.
• Supports genetic counseling and family risk assessment.
• Provides highly reliable molecular genetic results.
• Assists neurologists in clinical evaluation.
• Supports predictive and confirmatory testing when appropriate.
• Facilitates informed healthcare planning.

Why Doctors Recommend This Test

Doctors recommend Huntington Disease Mutation Analysis for individuals with symptoms suggestive of Huntington disease, patients with a family history of the condition, individuals undergoing neurological evaluation, and family members seeking genetic risk assessment after appropriate genetic counseling.

The test provides definitive molecular evidence regarding the presence or absence of disease-causing HTT gene expansions.

Preparation Before Test

• No fasting is required.
• A blood sample is collected for genetic analysis.
• Genetic counseling may be recommended before testing.
• Provide family history information if available.
• Inform your doctor about relevant neurological symptoms.
• Follow all sample collection instructions carefully.

Normal Reporting Time

Most Huntington Disease Mutation Analysis CAG Repeats reports at Focus Diagnostics are initiated within 2–3 hours for specimen processing and molecular workflow setup. Final genetic analysis, repeat sizing, validation, and reporting are generally completed within several working days depending on laboratory protocols and quality assurance procedures.

Who Should Take This Test?

This test may be recommended for:

• Individuals with symptoms suggestive of Huntington disease.
• People with a family history of Huntington disease.
• Patients with unexplained movement disorders.
• Individuals with progressive neurological symptoms.
• People seeking genetic risk assessment after counseling.
• Patients referred by neurologists.
• Adults undergoing predictive genetic testing.
• Individuals requiring confirmation of a clinical diagnosis.

Detailed Information

Huntington disease is a rare inherited neurodegenerative disorder caused by an expansion of CAG trinucleotide repeats within the HTT gene located on chromosome 4. The condition follows an autosomal dominant inheritance pattern, meaning that a child of an affected parent has a 50% chance of inheriting the mutation.

The HTT gene normally contains a certain number of CAG repeats. When the repeat count exceeds a disease-causing threshold, abnormal huntingtin protein is produced. This altered protein gradually damages nerve cells, particularly in regions of the brain responsible for movement, cognition, and behavior.

Symptoms of Huntington disease may include involuntary movements (chorea), balance difficulties, coordination problems, cognitive decline, mood changes, depression, personality changes, and behavioral disturbances. The age at symptom onset can vary, and larger repeat expansions are often associated with earlier disease onset.

Mutation Analysis CAG Repeats testing measures the exact number of CAG repeats present in the HTT gene. The results help determine whether the repeat count falls within normal, intermediate, reduced-penetrance, or disease-associated ranges.

Because Huntington disease is inherited, genetic testing has important implications for both the individual being tested and their family members. Genetic counseling is strongly recommended before and after testing to help individuals understand the medical, psychological, and familial implications of the results.

Results should always be interpreted by qualified healthcare professionals together with clinical findings, neurological evaluation, family history, and genetic counseling assessment.

At Focus Diagnostics, Huntington Disease Mutation Analysis CAG Repeats testing is performed using advanced molecular genetic platforms, validated repeat expansion analysis methodologies, and stringent quality assurance standards to provide accurate, reliable, and clinically meaningful genetic diagnostic results.