Spit in a tube, post it to a lab, and receive your ancestry, disease risks, and ideal diet by email: direct-to-consumer genetic testing has arrived in India with the full Silicon Valley playbook. Meanwhile, clinical genetic testing, ordered by doctors for suspected inherited conditions, is quietly transforming the diagnosis of rare diseases, cancers and prenatal conditions. The two worlds share technology but little else. Understanding what DNA tests can and cannot tell you is essential in a market where marketing routinely outruns science.

How genetic testing works

All genetic tests read DNA, but they read different amounts. Genotyping chips, used by consumer ancestry kits, sample a few hundred thousand known variants across the genome, cheap but incomplete. Gene panels sequence dozens to hundreds of genes relevant to a condition, such as cancer-predisposition genes. Exome sequencing reads the protein-coding 1 to 2 per cent of the genome where most disease-causing variants live, and is the workhorse for diagnosing rare diseases in children. Whole-genome sequencing reads everything, generating the most data and the most uncertainty. Bigger is not always better: more data means more variants of unknown significance, findings that cannot be interpreted.

What clinical testing does well

• Rare disease diagnosis: exome sequencing now diagnoses 30 to 50 per cent of children with suspected genetic disorders after years of diagnostic odyssey, ending the search and guiding care and family planning.
• Cancer predisposition: BRCA1 and BRCA2 testing identifies families at high risk of breast and ovarian cancer, enabling preventive action; similar panels exist for colorectal and other cancers.
• Prenatal and carrier screening: identifies couples at risk of passing on conditions like thalassemia, sickle cell disease and spinal muscular atrophy, which are significant in India.
• Pharmacogenomics: variants affecting drug metabolism can guide dosing for some medicines, though routine use is still limited.

What consumer kits cannot do

The disease-risk reports from consumer kits are the problem area. Most common diseases, diabetes, heart disease, depression, arise from hundreds of variants plus environment; a chip-based polygenic score gives a statistical nudge, not a prediction, and its accuracy in Indian populations is poorer because the underlying research was done overwhelmingly in Europeans. Ancestry reports are entertainment-grade estimates, not genealogy. Fitness and nutrition DNA reports, your genes say you should eat more protein, rest on the thinnest evidence in genomics. And consumer tests can miss clinically important variants: a negative BRCA result from a chip test does not rule out BRCA mutations the way clinical sequencing does, a genuinely dangerous misunderstanding.

The Indian context: consanguinity and counselling

India’s high rates of consanguineous marriage in some communities raise the prevalence of recessive genetic disorders, making carrier screening particularly valuable. At the same time, genetic counselling, the specialty that interprets results and guides families, is scarce, with only a few hundred trained counsellors nationally. Testing without counselling risks misinterpreted results, unnecessary anxiety, and, in prenatal contexts, pressured decisions. Any significant genetic test in India should ideally flow through a clinician or counsellor, not straight from a couriered kit to an email inbox.

Privacy and ethical concerns

Your genome identifies you uniquely and reveals information about your relatives, who never consented to testing. Consumer companies’ privacy policies vary; some share anonymised data with pharmaceutical partners, and anonymisation of genetic data is notoriously leaky. In India, regulation of genetic data is still evolving. Think carefully before uploading your DNA to any database, and understand that law enforcement, insurers and employers in some jurisdictions have sought such data. Clinical testing within the healthcare system carries stronger confidentiality protections.

FAQs

Should I get a consumer DNA test for health reasons? For entertainment and curiosity, fine. For medical decisions, no; see a doctor about clinical testing instead.

Will a genetic test tell me if I will get Alzheimer’s or cancer? Only for rare single-gene forms. For common diseases, tests estimate modest risk adjustments, not destiny; lifestyle and screening matter far more.

How much does clinical genetic testing cost in India? Gene panels typically 15,000 to 30,000 rupees, exome sequencing 30,000 to 60,000, falling steadily; many labs now offer them domestically.

Genetic testing is a powerful medical tool wearing, in its consumer form, an entertainment costume. Used clinically with counselling, it ends diagnostic odysseys, guides cancer prevention and informs family planning. Used casually for disease prediction, it mostly produces expensive anxiety. The genome is not a horoscope; read it with a professional, for a reason, or enjoy the ancestry pie chart for what it is.

Compiled by the Khabar 24h Editorial Desk from publicly available sources.