Leukaemia
is a group of blood cancers that usually begin in the bone and produce high numbers of abnormal blood cells. These blood cells are not fully developed and are called blasts or leukemia cells. Signs and symptoms may include bleeding and bruising, bone pain, , fever, and an increased risk of . These symptoms occur due to a lack of normal blood cells. is typically made by blood tests or bone marrow .
Underlined words are explained — tap any of them.
Symptoms — what it feels like
- ·Bleeding, bruising, , fever, increased risk of
Causes — why it happens
- ·Inherited and environmental factors
How it's found
- ·Blood tests, bone
Treatment
- ·, therapy, targeted therapy, bone , supportive care
Outlook
- ·Five-year survival rate 69% (U.S.)
The sections below are general education drawn from public guidelines (NHS, Mayo, CPIC, WHO, ICMR). They are not individually reviewed by a clinician and are not medical advice — always talk to a doctor about your own health.
Genes that change how certain drugs work — and that differ in South Asians. This is education, not a dosing tool; genotype-guided prescribing is a clinician decision.
Thiopurines are strong drugs that your body has to clear away safely using a cleanup called . If your gene makes little or none of it, the drug builds up and can crash your blood counts - so people with this gene version need a much smaller dose or a different drug.
South Asian signal: NUDT15 c.415C>T (rs116855232, the *3 defining variant) has a minor allele frequency of ~6.7% in South Asians per gnomAD (vs ~10.5% in East Asians) - far higher than TPMT risk alleles, which are only ~1.4-2.5% in Asians. In Indian paediatric ALL patients, NUDT15 variants were found in 16.7% vs TPMT*3C in only 3.3% (PMC12722899).
Prescriber note: In South Asian patients, NUDT15 c.415C>T is the higher-yield thiopurine safety test than TPMT; a heterozygous (intermediate) or homozygous (poor metaboliser) result mandates a reduced starting dose or alternative agent with close CBC monitoring. CPIC recommends reducing the thiopurine starting dose for NUDT15 intermediate metabolisers and substantially reducing or avoiding thiopurines for poor metabolisers, to prevent life-threatening myelosuppression; in Asians, NUDT15 predicts toxicity better than TPMT.
Not a dosing tool. Genotype-guided prescribing is a clinician decision; genotyping access in India is limited.
is a second cleanup for the same family of drugs. Some people are born making very little of it, so the medicine piles up and harms the bone . Testing it alongside tells the doctor how much drug is safe.
South Asian signal: TPMT no-function alleles are relatively uncommon in South/East Asians (~1.4-2.5%), notably lower than in Europeans and Africans; in Indian paediatric ALL, TPMT*3C heterozygosity was ~3.3% vs NUDT15 variants at 16.7% (PMC12722899). This is why NUDT15 carries more of the toxicity signal in this population.
Prescriber note: Test TPMT together with NUDT15 before starting thiopurines; a normal TPMT does not reassure in a South Asian patient because NUDT15 deficiency is the more common cause of toxicity here. Let the more deficient of the two genes govern dosing. CPIC recommends reduced thiopurine dosing for TPMT intermediate metabolisers and major dose reduction or avoidance for poor metabolisers; TPMT and NUDT15 are interpreted jointly, with the more severe phenotype driving the decision.
Not a dosing tool. Genotype-guided prescribing is a clinician decision; genotyping access in India is limited.
Some people are born with red blood cells that can't handle certain 'stressful' medicines. Give those drugs and the red cells burst, causing sudden . A simple blood test tells the doctor whether a drug like an anti-malaria pill is safe for that person.
South Asian signal: G6PD deficiency is common across India: an all-India systematic review found an overall ~1.9% prevalence (range 0.8-6.3%), but tribal/vulnerable groups run far higher - ~7.7% overall in tribal communities and up to ~27% in some groups. The G6PD Mediterranean (563C>T) variant, a severe (Class II) variant, is the commonest deficient allele in India (~60% of deficient cases), so many Indian deficients are the high-risk severe type.
Prescriber note: Screen for G6PD status before prescribing primaquine/tafenoquine (radical cure of vivax malaria), dapsone, or rasburicase; rasburicase is contraindicated in G6PD deficiency. Because the severe Mediterranean variant predominates in India, do not assume mild African-type deficiency. CPIC advises that in G6PD-deficient individuals, drugs with haemolytic potential (e.g. rasburicase - formally contraindicated; primaquine, dapsone, and other listed oxidants) should be avoided or used only with explicit risk-benefit justification and monitoring, and that higher-risk ancestries be screened before such drugs.
Not a dosing tool. Genotype-guided prescribing is a clinician decision; genotyping access in India is limited.