Complete List of Diseases in NCERT Biology Class 11 & 12 (NEET)

A comprehensive, chapter-wise table of all diseases, causative agents, and symptoms from NCERT Class 11 & 12 Biology. Perfect for quick NEET revision!

Here is a comprehensive list of the major diseases and disorders mentioned in the NCERT Class 11 and 12 Biology textbooks, organized logically by category to aid your NEET preparation.

1. Infectious Diseases (Human Health and Disease - Class 12)

S.No.	Disease Name	Causative Agent / Cause	Characteristic Symptoms
1	Typhoid	Salmonella typhi (Bacterium)	Sustained high fever (39°C - 40°C), weakness, stomach pain, constipation, headache, loss of appetite. Intestinal perforation in severe cases.
2	Pneumonia	Streptococcus pneumoniae, Haemophilus influenzae (Bacteria)	Fever, chills, cough, headache. Alveoli get filled with fluid. In severe cases, lips and fingernails turn gray to bluish.
3	Common Cold	Rhino viruses	Nasal congestion and discharge, sore throat, hoarseness, cough, headache, tiredness (lasts 3-7 days).
4	Malaria	Plasmodium (P. vivax, P. malaria, P. falciparum) (Protozoan)	Chills and high fever recurring every 3 to 4 days (due to release of hemozoin toxin from ruptured RBCs).
5	Amoebiasis (Amoebic dysentery)	Entamoeba histolytica (Protozoan)	Constipation, abdominal pain, cramps, stools with excess mucous and blood clots.
6	Ascariasis	Ascaris lumbricoides (Intestinal roundworm)	Internal bleeding, muscular pain, fever, anemia, blockage of the intestinal passage.
7	Filariasis (Elephantiasis)	Wuchereria (W. bancrofti, W. malayi) (Filarial worm)	Chronic inflammation of the lymphatic vessels (usually lower limbs), resulting in gross deformities. Genital organs are also often affected.
8	Ringworm	Microsporum, Trichophyton, Epidermophyton (Fungi)	Appearance of dry, scaly lesions on various body parts (skin, nails, scalp) accompanied by intense itching.
9	AIDS	Human Immunodeficiency Virus (HIV)	Progressive decrease in helper T-lymphocytes ($T_H$ cells), leading to severe immunodeficiency and opportunistic infections (like Mycobacterium, Toxoplasma).

2. Genetic Disorders (Principles of Inheritance and Variation - Class 12)

S.No.	Disease Name	Causative Agent / Cause	Characteristic Symptoms
10	Colour Blindness	Sex-linked recessive trait (mutation in X chromosome)	Inability to distinguish between red and green colors.
11	Haemophilia	Sex-linked recessive trait	A single protein involved in blood clotting is affected; a simple cut results in non-stop bleeding.
12	Sickle-cell anaemia	Autosomal recessive trait (Substitution of Glutamic acid by Valine at 6th position of $\beta$-globin chain)	RBCs become sickle-shaped under low oxygen tension, causing anemia and blockages in blood vessels.
13	Phenylketonuria (PKU)	Autosomal recessive trait (Lack of enzyme phenylalanine hydroxylase)	Accumulation of phenylalanine (and its derivatives) in the brain leading to mental retardation, hair loss, and skin pigmentation.
14	Thalassemia	Autosomal recessive trait (Mutation in $\alpha$ or $\beta$ globin genes)	Reduced rate of synthesis of one of the globin chains, resulting in the formation of abnormal hemoglobin and severe anemia.
15	Down's Syndrome	Aneuploidy: Trisomy of Chromosome 21 (47 chromosomes)	Short stature, small round head, furrowed tongue, partially open mouth, broad palm with characteristic palmar crease, mental retardation.
16	Klinefelter's Syndrome	Aneuploidy: Extra X chromosome in males (47, XXY)	Overall masculine development, but feminine traits are expressed (e.g., development of breasts / Gynaecomastia). Individuals are sterile.
17	Turner's Syndrome	Aneuploidy: Absence of one X chromosome in females (45, XO)	Females are sterile with rudimentary ovaries, short stature, and lack of secondary sexual characters.

3. Physiological and Nutritional Disorders (Class 11)

S.No.	Disease Name	Causative Agent / Cause	Characteristic Symptoms
18	Kwashiorkor	Protein deficiency (Affects children > 1 year old)	Wasting of muscles, thinning of limbs, failure of growth, extensive brain development delay, but fat is still left under the skin, extensive edema (swelling).
19	Marasmus	Protein and Calorie deficiency (Affects infants < 1 year old)	Extreme emaciation of the body, thinning of limbs, skin becomes dry, thin, and wrinkled. Decline in growth rate.
20	Asthma	Inflammation of bronchi and bronchioles (often allergic)	Difficulty in breathing causing wheezing.
21	Emphysema	Chronic cigarette smoking (Alveolar walls get damaged)	Respiratory surface area is severely decreased, leading to chronic shortness of breath.
22	Coronary Artery Disease (Atherosclerosis)	Deposition of calcium, fat, cholesterol, and fibrous tissue	Narrowing of the lumen of coronary arteries, reducing blood supply to heart muscles.
23	Angina Pectoris	Inadequate oxygen supply to the heart muscle	Acute chest pain. Can occur in men and women of any age but common in middle-aged and elderly.
24	Uremia	Kidney malfunction	Accumulation of urea in the blood, which is highly toxic and can lead to kidney failure.
25	Renal Calculi	Insoluble mass of crystallized salts (e.g., oxalates)	Stones formed within the kidney, causing severe pain.
26	Myasthenia gravis	Autoimmune disorder affecting the neuromuscular junction	Fatigue, weakening, and paralysis of skeletal muscles.
27	Muscular dystrophy	Genetic disorder	Progressive degeneration of skeletal muscles.
28	Tetany	Low $Ca^{2+}$ in body fluids	Rapid spasms (wild contractions) in muscles.
29	Osteoporosis	Age-related disorder; decreased levels of estrogen	Decreased bone mass and increased chances of bone fractures.
30	Gout	Accumulation of uric acid crystals	Inflammation and intense pain in the joints.

4. Endocrine/Hormonal Disorders (Chemical Coordination and Integration - Class 11)

S.No.	Disease Name	Causative Agent / Cause	Characteristic Symptoms
31	Gigantism	Over-secretion of Growth Hormone (GH) before puberty	Abnormal, excessive growth of the body.
32	Acromegaly	Over-secretion of GH in adults (middle age)	Severe disfigurement (especially of the face), which can lead to serious complications and premature death if unchecked.
33	Dwarfism	Low secretion of GH	Stunted body growth.
34	Goitre	Iodine deficiency in the diet	Enlargement of the thyroid gland.
35	Cretinism	Hypothyroidism during pregnancy	Defective development and stunted growth of the baby, mental retardation, low IQ, abnormal skin, deaf-mutism.
36	Graves' Disease (Exophthalmic goitre)	Hyperthyroidism (often autoimmune)	Enlargement of the thyroid gland, protrusion of the eyeballs, increased basal metabolic rate (BMR), and weight loss.
37	Addison's Disease	Underproduction of adrenal cortex hormones	Altered carbohydrate metabolism causing acute weakness, fatigue, and bronze-like skin pigmentation.
38	Diabetes Mellitus	Insufficient insulin secretion / Insulin resistance	Prolonged hyperglycemia, loss of glucose through urine (Glycosuria), formation of harmful ketone bodies (Ketonuria).
39	Diabetes Insipidus	Deficiency or impairment of ADH (Vasopressin)	Inability of the kidney to conserve water leading to excessive urination (diuresis) and dehydration.