Name of the Procedure:

SNRPN/UBE3A Methylation Analysis (commonly referred to as Prader-Willi syndrome and Angelman syndrome methylation analysis)

Summary

SNRPN/UBE3A methylation analysis is a genetic test used to diagnose Prader-Willi syndrome (PWS) and Angelman syndrome (AS). It examines the methylation patterns of the SNRPN and UBE3A genes, which can indicate abnormalities associated with these syndromes.

Purpose

This procedure is used to diagnose Prader-Willi syndrome and Angelman syndrome, both of which are genetic disorders that affect development and behavior. The goal is to identify abnormal methylation patterns in the SNRPN and UBE3A genes that are indicative of these syndromes.

Indications

• Symptoms such as poor muscle tone, feeding difficulties, and developmental delays in infants.
• Behavioral problems, intellectual disabilities, and characteristic facial features.
• Failure to achieve developmental milestones.
• Suspicion of PWS or AS based on clinical observations and family history.

Preparation

• No specific preparation is typically required from the patient.
• A blood sample or cheek swab may be collected for analysis.
• Patients should inform their doctor of any relevant family genetic history.

Procedure Description

1. A blood sample or cheek swab is collected from the patient.
2. The sample is sent to a laboratory where DNA is extracted.
3. The DNA undergoes bisulfite treatment to convert unmethylated cytosines into uracil, while methylated cytosines remain unchanged.
4. Polymerase Chain Reaction (PCR) amplifies the region of interest containing the SNRPN and UBE3A genes.
5. The methylation patterns are analyzed using methylation-specific PCR or next-generation sequencing techniques.
6. Results are compared to normal profiles to identify abnormalities.

Duration

The sample collection takes only a few minutes. Laboratory analysis can take several days to a few weeks.

Setting

• The sample collection occurs in a medical office, hospital, or outpatient clinic.
• Analysis is conducted in a specialized genetics laboratory.

Personnel

• Sample collection is typically done by a nurse or phlebotomist.
• Geneticists and laboratory technicians perform the analysis.
• A genetic counselor or physician provides results interpretation.

Risks and Complications

• The sample collection process carries minimal risks, such as slight discomfort or bruising at the blood draw site.
• There are no significant risks associated with the genetic analysis itself.

Benefits

• Accurate diagnosis of Prader-Willi syndrome or Angelman syndrome.
• Early diagnosis can lead to appropriate interventions and management strategies.
• Families receive crucial information for genetic counseling and future family planning.

Recovery

• No recovery time is required after the sample collection.
• Patients can resume normal activities immediately after the procedure.

Alternatives

• Clinical diagnosis based on physical symptoms and developmental milestones.
• Other genetic tests such as chromosomal microarray analysis or gene sequencing may be used to confirm the diagnosis.
• Each alternative has its own benefits and limitations; genetic counseling can help determine the best approach.

Patient Experience

• Patients may feel minor discomfort during blood sample collection.
• They will not experience any direct effects from the laboratory analysis.
• Informative results can lead to significant emotional relief or preparation for future care.