Beta Hexosaminidase A (GM2-1) / Tay-Sachs Disease Test

Test Overview

The Beta Hexosaminidase A (Hex A) Test is a specialized diagnostic test used to detect Tay-Sachs Disease and related GM2 gangliosidosis disorders. It measures the activity of the Hexosaminidase A enzyme in blood samples. Deficiency or absence of this enzyme leads to the accumulation of fatty substances (GM2 gangliosides) in nerve cells, causing progressive neurological damage.

This test is commonly used for:

• Diagnosis of Tay-Sachs disease
• Carrier screening
• Prenatal and family risk assessment
• Evaluation of neurodegenerative symptoms in infants and children

Sample Type

• Specimen: Blood

Why This Test is Done

Doctors may recommend this test for:

• Developmental delay in infants
• Muscle weakness or loss of motor skills
• Seizures or neurological symptoms
• Family history of Tay-Sachs disease
• Carrier screening before pregnancy
• Genetic counseling evaluation

About Tay-Sachs Disease

Tay-Sachs disease is a rare inherited genetic disorder caused by mutations in the HEXA gene, leading to deficiency of the Hex A enzyme.

Common Symptoms

Infantile Form

• Loss of developmental milestones
• Exaggerated startle response
• Muscle weakness
• Vision and hearing loss
• Seizures

Later-Onset Forms

• Difficulty walking
• Speech problems
• Muscle weakness
• Coordination issues

Test Method

• Enzyme Activity Assay
• Fluorometric / Biochemical Analysis

Preparation

• No special preparation is usually required.
• Inform your doctor about any medications or recent transfusions.

Interpretation of Results

Normal

• Normal Hexosaminidase A enzyme activity detected

Abnormal

• Reduced or absent enzyme activity may indicate:
  • Tay-Sachs disease
  • Carrier status
  • Other GM2 gangliosidosis disorders

Further genetic testing may be recommended for confirmation.

Who Should Consider Testing?

• Individuals with family history of Tay-Sachs disease
• Couples planning pregnancy
• High-risk ethnic populations
• Infants with unexplained neurological symptoms

Turnaround Time

• Typically: 5–10 days
  (May vary by laboratory)

Clinical Significance

Early detection helps in:

• Genetic counseling
• Family planning decisions
• Early supportive care
• Risk assessment for future pregnancies

Disclaimer

This test is intended for diagnostic and screening purposes and should be interpreted by a qualified healthcare professional along with clinical findings and other laboratory investigations.