81416 Exome (eg, unexplained constitutional or heritable disorder or syndrome); sequence analysis, each comparator exome (eg, parents, siblings) (List separately in addition to code for primary procedure)

Name of the Procedure:

Exome sequencing, each comparator exome (e.g., parents, siblings); List separately in addition to code for primary procedure
Common names: Exome Sequencing, Comparator Exome Sequencing

Summary

Exome sequencing is a genetic testing procedure that examines the coding regions of all genes (exons) in the DNA. This specific procedure involves comparing the exome sequences of the patient with those of close relatives (e.g., parents, siblings) to help diagnose unexplained constitutional or heritable disorders or syndromes.

Purpose

Exome sequencing aims to identify genetic mutations that may be responsible for unexplained or inherited medical conditions. The goal is to diagnose genetic disorders and guide treatment decisions by comparing the patient's exome to those of family members, providing a clearer picture of potential hereditary patterns.

Indications

• Unexplained developmental delays
• Congenital anomalies
• Suspected genetic disorders with unknown causes
• Family history of heritable conditions or syndromes
• Cases where standard diagnostic tests have failed to identify a cause

Preparation

• No extensive preparation is generally required.
• Patients might be advised to avoid certain medications and to provide a detailed family medical history.
• A blood sample might be required from both the patient and family members.

Procedure Description

1. Sample Collection: Blood samples are taken from the patient and each comparator (parents, siblings).
2. DNA Extraction: DNA is isolated from the blood samples.
3. Library Preparation: The exome regions of the DNA are targeted and prepared for sequencing.
4. Sequencing: High-throughput sequencing technology is used to read the exome sequences.
5. Data Analysis: The genetic sequences are compared to identify mutations and their potential link to the patient's condition.

Duration

The primary sample collection typically takes about 30 minutes. Sequencing and data analysis can take several weeks.

Setting

The procedure begins in a clinical setting (e.g., hospital or outpatient clinic) for sample collection. The sequencing and analysis are performed in a specialized laboratory.

Personnel

• Medical Geneticists
• Laboratory Technologists
• Genetic Counselors
• Nurses

Risks and Complications

• Mild discomfort or bruising at the blood draw site.
• Risk of uncovering unexpected genetic information that could have psychological or familial implications.

Benefits

• Potential for accurate diagnosis of unexplained or hereditary disorders.
• Provides a basis for targeted treatment and management plans.
• Helps in understanding familial genetic risks and informing family planning decisions.

Recovery

• Immediate resume to daily activities after the blood draw.
• No specific recovery time or restrictions.
• Follow-up appointments to discuss results and implications with a healthcare provider.

Alternatives

• Whole genome sequencing: More comprehensive but more expensive and time-consuming.
• Single-gene testing: Less comprehensive, only tests one gene at a time.
• Chromosomal microarray analysis: Detects larger genetic changes but not small mutations.

Patient Experience

• Minimal discomfort during the sample collection.
• No pain or physical sensations from the sequencing process itself.
• Counseling might be needed to handle the emotional and psychological impact of the results.