Cytogenomic constitutional (genome-wide) microarray analysis; interrogation of genomic regions for copy number and single nucleotide polymorphism (SNP) variants for chromosomal abnormalities
CPT4 code
Name of the Procedure:
Cytogenomic Constitutional (Genome-Wide) Microarray Analysis; Interrogation of Genomic Regions for Copy Number and Single Nucleotide Polymorphism (SNP) Variants for Chromosomal Abnormalities
Summary
Cytogenomic constitutional microarray analysis is a diagnostic test that examines the entire genome to detect variations in DNA. It identifies specific regions of the chromosomes that have gained or lost copies (copy number variations) and single nucleotide polymorphisms (SNPs), which can cause genetic disorders.
Purpose
The test is used to diagnose various genetic conditions and chromosomal abnormalities, such as developmental delays, congenital anomalies, and unexplained intellectual disabilities. The goal is to identify genetic causes of these conditions to provide accurate diagnoses and inform treatment plans.
Indications
- Unexplained developmental delay or intellectual disability
- Multiple congenital anomalies
- Autism spectrum disorders
- Suspected chromosomal abnormalities
- Recurrent pregnancy loss
Preparation
Patients generally do not need any special preparation for this test. However, a clinical genetics evaluation may be required beforehand. Fasting and medication adjustments are typically unnecessary.
Procedure Description
- A blood sample is collected from the patient.
- DNA is extracted from the blood cells.
- The DNA is then placed on a microarray, a special chip that holds thousands of DNA sequences.
- The microarray scans the DNA for abnormalities in copy number and SNPs.
- Specialized software analyzes the data, identifying any genetic variations.
No sedation or anesthesia is needed for this non-invasive procedure, as it simply involves drawing a blood sample.
Duration
The actual blood draw takes about 5-10 minutes. The analysis and interpretation can take several days to a couple of weeks, depending on the laboratory.
Setting
The blood sample collection is typically done in a clinical setting such as a hospital, outpatient clinic, or diagnostic lab. The DNA analysis is performed in a specialized laboratory.
Personnel
- Phlebotomist or nurse for blood sample collection
- Laboratory technicians and geneticists for sample analysis
- Clinical geneticist or genetic counselor for result interpretation and patient counseling
Risks and Complications
The primary risk is minor and related to blood draw, such as slight bruising or discomfort at the puncture site. There are no significant risks associated with the microarray analysis itself.
Benefits
The primary benefit is the accurate identification of genetic abnormalities, which can lead to a tailored treatment plan and better management of the condition. It often provides more detailed information compared to traditional karyotyping.
Recovery
There is no recovery time needed for the blood draw. Patients can resume normal activities immediately afterward. Follow-up care may include consultations with a genetic counselor or relevant specialists depending on the results.
Alternatives
- Karyotyping: less detailed, traditional method for examining chromosomes.
- Fluorescence In Situ Hybridization (FISH): used for specific genetic disorders but less comprehensive.
- Whole genome sequencing: provides more detailed information but is more expensive and time-consuming.
Each alternative has its pros and cons in terms of cost, detail, and applicability to specific genetic conditions.
Patient Experience
The patient will experience a standard blood draw, which might cause slight discomfort. Emotional support from a genetic counselor may be offered, especially if the results indicate a serious genetic condition. Pain management is generally not necessary due to the simplicity of the blood draw.