Turnaround time: NGS takes 2-4 weeks (cancer patients may not have that time)
Data interpretation: AI helps, but many variants still unclassified
Equity: Genomic databases biased toward European ancestry → worse predictions for African, Asian populations
Recall Explain to a 12-Year-Old
Imagine your body is like a LEGO set. Everyone gets the same basic instruction manual (the human genome), but some people have typos in their manual—maybe one piece is a slightly different shape.
Old medicine was like giving everyone the same replacement piece when something broke. But if your typo made your piece a different shape, the standard replacement doesn't fit!
Precision medicine reads your specific manual (your DNA), finds your unique typos, and makes a custom piece just for you.
For example:
Some kids can't process milk (lactose intolerance) because of a gene typo → we don't force them to drink milk
Some people break down medicine super slowly → they need a lower dose or they get sick
It's like having a custom video game difficulty: the game adjusts to your skill level instead of treating everyone the same.
What is precision medicine? :: An approach to treatment and prevention that accounts for individual variability in genes, environment, and lifestyle, using genomic data to tailor therapies to each patient.
What are the two main types of genomic sequencing in precision medicine?
(1) Germline sequencing (inherited DNA from blood/saliva) and (2) Somatic sequencing (tumor-specific mutations from biopsy).
Why do BRCA1 mutation carriers have higher breast cancer risk?
BRCA1 is a DNA repair gene. Loss-of-function mutations impair homologous recombination repair, leading to accumulation of mutations and cancer (55-72% lifetime risk vs 12% general population).
What is pharmacogenomics?
The study of how genes affect a person's response to drugs, predicting efficacy and side effects based on variants in metabolizing enzymes (e.g., CYP2C9 for warfarin).
Why do CYP2C9 *3 carriers need lower warfarin doses? :: CYP2C9 *3 is a slow-metabolizer allele. Warfarin is cleared more slowly, leading to accumulation and increased bleeding risk if dosed normally.
What is ctDNA and why is it useful in cancer monitoring?
Circulating tumor DNA—fragments of cancer DNA shed into the bloodstream. Sequencing ctDNA detects new resistance mutations earlier than imaging, guiding therapy switches.
What mutation is targeted by osimertinib in lung cancer?
EGFR exon 19 deletion or L858R mutation. Osimertinib is an EGFR tyrosine kinase inhibitor that blocks the overactive mutant EGFR protein driving tumor growth.
What is the difference between pathogenic and VUS variants?
Pathogenic variants are confirmed disease-causing; VUS (variant of uncertain significance) have unclear impact—may benign, pathogenic, or neutral. VUS requires further evidence before clinical action.
Why is precision medicine less effective for polygenic diseases?
Polygenic diseases (diabetes, heart disease) result from many variants with small individual effects + environment. Hard to predict or target with single therapies, unlike monogenic diseases with one strong mutation.
What is a common ethical concern in precision medicine?
Genetic discrimination—insurance or employers using genomic data to deny coverage/employment; also incidental findings (learning disease risks unrelated to the test's purpose).
Precision medicine ka matlab hai ki ab har patient koek hi jaisa treatment nahi milega. Pehle sab ko same dawai, same dosete the—jaise ek hi size ki shirt sabko pehnane kioshish. Lekin har insaan ki genetic makeup alag hoti hai, toh response bhi alag hota hai.
Ab genomic sequencing se hum patient ka DNA padhte hain aur uski specific mutations dekh kar decide karte hain ki konsi drug kaam karegi aur konsi nahi. Example: agar lung cancer patient ke tumor mein EGFR mutation hai, toh hum osimertinib jaisi targeted therapy dete hain jo us mutant protein ko directly block karti hai—chemo se behtar results aur kam side effects.Isi tarah, warfarin jaisi blood thinner ki dose bhi ab genes (CYP2C9) ke basis par adjust karte hain, taki bleeding ya clotting na ho.
Yeh approach prevention mein bhi help karta hai:agar kisi ko BRCA1 mutation mili, toh uski breast cancer risk 70% tak badh jati hai, toh hum pehle se hi intensive screening ya preventive surgery suggest kar sakte hain. Lekin challenges bhi hain—genomic testing mehnga hai, sab variants ka matlab clear nahi hota (VUS—variant of uncertain significance), aur ethical issues bhi hain (insurance discrimination, incidental findings). Overall, precision medicine ek powerful tool hai jo future mein standard care ban sakta hai, par abhi limitations bhi accept karni padti hain.