Karyotyping - Prenatal
In cases of an unexplained mental retardation and developmental delays in the family history, routine chromosome analysis (minimum 550-band resolution) is recommended.1
Cytogenetic analysis should be performed for children with clinical features of known chromosomal abnormality syndromes, as the identification of a translocation may impact the family's recurrence risk1
Karyotyping can detect major chromosomal abnormalities, such as structural aneuploidies ( translocations, inversions, polymorphic variants) & numerical aneuploidies.
Karyotype tests can be used for more than finding birth defects.
- Trouble getting pregnant or have had several miscarriages
- You can find out if you have a disorder that you could pass down to your child.
- They can find the cause of certain physical or developmental problems your baby or young child has.
- Chromosome tests can show whether a newborn is a boy or a girl in the rare cases where it isn’t clear.
- Certain kinds of cancer can cause chromosome changes. Karyotype testing can help get you the right treatment
Clinical Utility
- Karyotyping plays a crucial role in prenatal diagnosis by examining fetal chromosomes to detect chromosomal abnormalities in the developing fetus.
- Constitutional disorders: Karyotyping assists in identifying constitutional chromosomal abnormalities that can lead to developmental delays, intellectual disabilities, and birth defects. It provides important information for genetic counseling and family planning.
- Karyotyping is employed to investigate the underlying chromosomal causes of recurrent pregnancy loss, infertility, and stillbirths. It helps identify chromosomal abnormalities that may affect reproductive health and guides appropriate management strategies.
- Karyotyping results provide valuable information for genetic counseling, enabling healthcare providers to offer guidance, support, and informed decision-making to individuals and families.
When is it recommended
- Advanced maternal age (typically over 35 years).
- Abnormal prenatal screening test results.
- Family history of chromosomal disorders or genetic conditions.
- Previous child with a chromosomal abnormality.
- Abnormal ultrasound findings suggesting potential chromosomal abnormalities.
- Parental carrier of balanced chromosomal rearrangements.
- Consanguinity (related by blood) between parents.
- Parental concern or request for comprehensive chromosomal analysis.
- History of recurrent pregnancy loss.
- Suspected mosaicism (presence of cells with different chromosomal makeup) in a parent or previous child.
Test specification
| Technique | Variant types | TAT | Sample requirements |
|---|---|---|---|
| G - Band | AS + SV | 10-12 days, 18 days for Prenatal | Serum heparin Blood 2-3 ml, CVS |
References
- Shaffer, Lisa G, and American College of Medical Genetics Professional Practice and Guidelines Committee. “American College of Medical Genetics guideline on the cytogenetic evaluation of the individual with developmental delay or mental retardation.” Genetics in medicine : official journal of the American College of Medical Genetics vol. 7,9 (2005): 650-4.
FAQs
When is karyotyping recommended?
Karyotyping may be recommended when there are signs or symptoms that suggest a chromosomal abnormality, such as developmental delays, intellectual disabilities, birth defects, infertility, recurrent pregnancy loss, or certain types of cancer. It can be performed at different stages, including prenatal diagnosis (during pregnancy) or postnatal diagnosis (after birth).