Genetics is the study of how certain traits and risk for diseases are passed to children from their parents. Learn about genetic disorders and available genetic testing options.
Genetics is a novel and rapidly growing field of medicine. Genetic disorders were previously considered rare and not worth looking for. However, in a country like India with 130 crore population, we are expected to see more patients with genetic disorders than any other country in the world. The need of the hour is that we clinicians should actively look for the markers of genetic disease and start diagnosing and treating patients accordingly.
Who Needs Genetic Evaluation?
Couples with previously affected children.
Genetic problems in parents.
Parents known carrier for a genetic disorder.
Family history of genetic problems.
Anomaly in an ongoing pregnancy.
Positive screening test for Trisomy.
Multiple pregnancy losses.
Advanced maternal age.
Teratogen exposure, that is, drugs, radiation, or evidence of viral infections like chickenpox.
Family history of recurrent or rare cancers or childhood cancers.
Steps of Genetic Evaluation, Counseling, and Management:
Giving empathy and support to the unfortunate families.
Attempt to confirm a genetic diagnosis - Proper history, examination, clinical evaluation, narrowing down to probable and closer clinical diagnosis, followed by genetic testing.
Treatment – Curative or supportive.
Anticipatory guidance - The genetic disorder or the syndrome can have various evolving complications related to other organ systems; this can be looked for and managed early.
Risk prediction for next pregnancy or at-risk family member.
Identifying preventive strategies.
Possibility of prenatal diagnosis by chorionic villous sampling or amniocentesis or by pre-implantation genetic diagnosis.
Postnatal evaluation, and if needed, to do tests for the newborn.
Follow-up of the child after birth.
Offering reproductive options.
Offer solutions and support through parental support groups, governmental schemes, and charity organizations.
For Strategizing Next Pregnancy or Prevention:
Carrier screening for the parents.
Discussing the preventive options available.
Attempting early identification during pregnancy by testing or antenatal ultrasound.
Planning prevention by prenatal diagnosis.
Donor options based on the carrier status.
When to Refer or Evaluate a Family with a Genetic Disorder?
Pregnancy period - Ideal time, because it gives us enough time to analyze the problem and arrive at a diagnosis, proper planning, and monitoring of pregnancy and do interventions at the right time.
Ongoing pregnancy - For anomalies found in antenatal ultrasound, yes! But, if in case of an index child with an abnormality is referred for evaluation during the current pregnancy, it will give us very little time for testing the affected child and proceeding with the prenatal testing of the fetus.
Post-delivery - Abnormality found postnatally.
Premarital – Significant family history is suggestive of genetic disorders, particularly in close relatives.
The genetic testing options available are as follows:
FISH (Fluorescence in situ hybridization).
CGH (Comparative genomic hybridization) microarray.
qPCR (Qualitative polymerase chain reaction).
MLPA (Multiplex ligation-dependent probe amplification).
Sanger sequencing or next-generation sequencing.
Clinical or whole-exome sequencing.
All these tests are available in various labs across India and internationally, and most of these tests are done now at affordable pricing. The clinician’s responsibility is to motivate the family, making them realize the importance of these testing, giving them adequate time to save money and do these confirmatory tests. The selection of the test, reliability of the lab, and the interpretation of the results are the key factors in successful genetic testing and diagnosis.
Genetic disorders are not very uncommon in day to day pediatric practice. They carry a significant risk of recurrence too. Finding out the exact cause by proper testing helps the physician in providing effective management and anticipatory guidance. Screening of parents and family members, risk assessment for next pregnancy, and preventive strategies also help.
Last reviewed at:
12 Oct 2019 - 3 min read
MBBS, DCH, MD PEDIATRICS, Dip.NB, FELLOWSHIP IN CLINICAL GENETICS
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