Name of the Procedure:

SMPD1 Gene Analysis (Sphingomyelin Phosphodiesterase 1, Acid Lysosomal) (e.g., Niemann-Pick Disease, Type A) Common Variants (e.g., R496L, L302P, fsP330)

Summary

SMPD1 gene analysis is a blood test that detects mutations in the SMPD1 gene, which are associated with Niemann-Pick Disease, Type A. This genetic test identifies common variants such as R496L, L302P, and fsP330.

Purpose

The procedure is used to diagnose Niemann-Pick Disease, Type A, a rare genetic disorder. The test helps in identifying mutations in the SMPD1 gene that lead to the disease, aiding in early diagnosis and management.

Indications

• Newborns or infants presenting with symptoms such as enlargement of the liver and spleen (hepatosplenomegaly), failure to thrive, and neurodegeneration.
• Family history of Niemann-Pick Disease, Type A.
• Prenatal diagnosis in cases with known family history.

Preparation

• No special preparation or fasting required before the test.
• Inform the doctor about any medications currently being taken.
• A detailed family history may be collected.

Procedure Description

1. Blood sample collection from the patient, usually from a vein in the arm.
2. The sample is sent to a laboratory specialized in genetic testing.
3. DNA is extracted from the blood cells and analyzed for specific variants in the SMPD1 gene (e.g., R496L, L302P, fsP330) using techniques such as PCR and sequencing.

Duration

The blood collection takes about 5-10 minutes. The analysis and results may take a few weeks.

Setting

The blood draw is performed at a healthcare facility such as a hospital, clinic, or laboratory.

Personnel

• Phlebotomist or nurse for blood sample collection.
• Geneticist or lab technician for DNA analysis.
• Healthcare provider (e.g., genetic counselor, physician) for result interpretation and counseling.

Risks and Complications

• Minor risk of bruising or infection at the blood draw site.
• Rarely, patients may feel dizzy or faint during the blood draw.

Benefits

• Early and accurate diagnosis of Niemann-Pick Disease, Type A.
• Information to help guide treatment decisions and genetic counseling.
• Identification of carriers within the family can inform reproductive planning.

Recovery

• No specific recovery period is needed.
• Normal activities can be resumed immediately after the blood draw.

Alternatives

• Other forms of genetic testing that may focus on a broader range of mutations.
• Enzyme assay tests to measure sphingomyelinase activity.
  • Pros: Enzyme assays provide functional information.
  • Cons: May not be as specific or sensitive as direct genetic testing for known variants.

Patient Experience

• Minimal discomfort during blood draw, similar to a routine blood test.
• Follow-up with a healthcare provider for test results and next steps.
• Genetic counseling may be recommended to discuss the implications of the test results and potential impacts on family planning.