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Genetic disorders
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- 2. Introduction 03 04 01 02 Causes History Types •CONTENTS 05 Diseases
- 3. • A geneticdisorder is an illness caused by one or more abnormalities in the genome, especially a condition that is present from birth (congenital). • Genetic disorders may or may not be heritable. • Also can be due to changes in DNA Introduction •
- 4. Discovered genes areable to change positions on chromosomes Both made a model of the DNA molecule and proved genes determie heredity. Barbara McClintock Francis H.C Crick Experimented pea plant, and developed principles of inheritance Major role in understanding the structures of DNA & RNA Gregor Mendel Rosalind Franklin Arthur Kornberg James D. Watson Produced DNA in a Test tube. • History… @sources:google images
- 5. Cause 1 Cause 2 •An error during meiosis causing defects in sex cells • If only one gamet is involved in fertilization • Nondisjunctional causes Cause 3 • A defective gene present in one or both parents • Also known as hereditary disease • Early marriges • Spontaneous abortions • Late pregnencies • Causes
- 6. • Classifications Chromosomal disorders Those thatare caused by numarical or structural abnormilities of the chromosome 01 Single gene disorder Those that are caused by defects of a individual gene 02 03 04 Multifactorial disorders Those that are the result of the combines effect of genetic and enviromental factors Mitochondrial disorder Those that are affected due to mitochondrial defects
- 7. 1a. Down Syndrome ›Caused by trisomy in chromosome 21 › Mental retardation, flattened face, short stature › High risk of cardiac anomalies, leukaemia, cataracts and digestive blockage › Average life expectancy is 55years 1b. Edward Syndrome › Caused by trisomy in chromosome 18 › Skull and facial abnormalities, defected organs › Poor muscle tone › Average life expectancy is 2-4 months 1. Chromosomal disorders…
- 8. 1c. Patau Syndrome ›Caused by trisomy in chromosome 13 › Mental and physical retardation, have extra digit › Cleft lip & large triangular nose › Average life expectancy is 6 months 1d. Turner Syndrome › Caused due to monosomy in sex chromosome › Webbing of neck, lack of secondary sex characteristics, sexually underdeveloped › Mostly seen in females(1:3000) @sources:google images
- 9. 1e. Klinefelter Syndrome ›Due to trisomy in sex chromosome (XXY) › Tall stature, hypogonadism, lack of secondary male characteristics › Infertile due to reduced spermatogenesis › Common in male 1f. Super Female › An extra X chromosome is present (XXX-female) › Menstrual irregularities, slight mental retardation 1g. Super Male › An extra Y chromosome is present (XYY-male) › Usually unknown › Tall, acne issues, speech problems @sources:google images
- 10. 1h. Williams Syndrome ›Due to deletion in chromosome 7 › Delayed development, delayed speech, moderate mental retardation › Sunken chest, unusual appearance of the face 1i. Cri du Chat Syndrome › Due to deletion in chromosome 5 › Problem with larynx and nervous system › Drooling problem, difficulty in swallowing and sucking @sources:google images
- 11. 2a. Neurofibromatosis(NF) › Itis an Autosomal dominant disease › Mutation in chromosome number 17 › Tan spots on skin in mild cases › Causes severe deformities, tumours and even death 2b. Huntington’s Disease › Repeated sequence of AGC on chromosome 4 › Neurogenerative disorder › Loss of balance, memory loss, muscle jerks › Onset is between 35-45 years 2. Single Gene Disorders… @sources:google images
- 12. 2c. Cystic Fibrosis ›An autosomal recessive disorder › Mutation in chromosome 7 › Difficulty in breathing, lung infection › Thick mucous develops in lungs › Most common lethal genetic disorder 2d. Tay Sachs Disease › An autosomal recessive disorder › Mutation in HEXA gene › Gradual paralysis, loss of nervous functions › Heterozygote carrier are resistant to Tb. @sources:google images
- 13. 2e. Colour Blindness ›Sex link recessive disorder › Unable to see colour in normal way › Can’t distinguish between colours generally green, red and blue › Mostly in males 2f. Haemophilia › Sex link recessive disorder › Caused by inheritance of one recessive gene on X or both X › Blood doesn't clot › Risk of sever bleeding from common injuries › Common in males @sources:google images
- 14. 2h. Sickle CellAnaemia › Abnormality in haemoglobin › Cell becomes sickle shaped and clog blood vessels › Poor circulation of blood, anaemia, jaundice › Heterozygote carriers are resistant to malaria › Mutation in chromosome 11 2g. Severe Combined Immunodeficiency (SCID) › Mutation in the SCIDX1 gene in X chromosome › Defects in immune system › Chronic skin infection, diarrhea, hepatitis @sources:google images
- 15. 3. Multifactorial diseases… 3a.Asthma › Common chronic inflammatory disease › Inflammation in asthmatic airways › Wheezing, chest tightness, difficulty in breathing, coughing, etc are symptoms of asthma 3b. Autoimmune Disease › Arises from abnormal immune response to own body › Destroys normal body tissues › leads to more hypersensitive reactions @sources:google images
- 16. 3c. Cancer › Uncontrolledgrowth and spread of abnormal cells › Change in bowel habits or bladder functions › Unusual bleeding, coughing › Indigestion and difficulty in swallowing 3d. Heart Diseases › Fatty deposits of cholesterol- Atherosclerosis › Hypertension also leads to heat failure › Occurs when coronary arteries that supply the heart muscles became blocked › Uncomfortable pressure, fullness, chest discomfort, squeezing pain @sources:google images
- 17. 4. Mitochondrial Disorders… 4a.MELAS Syndrome › Due to mutation in mitochondria › Occurs in brain, blood gets too acidic › Most common inherited mitochondrial disease › Vomiting, migraine droopy eyelids, muscle weakness 4b. Renal Oncocytoma › Tumour of the kidney made of oncocytes › Tumour is densely packed with mitochondria › Presence of blood in urine, abdominal mass @sources:google images
- 18. • Diagnosis… o Prenataldiagnosis- Diagnosis of genetic disease or condition in the developing fetus o Presymptomatic genetic testing- Can tell if a person with a family history for a genetic disease but does not have symptoms. o Preimplantation studies- Used only in in-vitro fertilization to diagnose a genetic disease in an embryo before it is implanted into the mother's uterus. o Predictive genetic testing- Can tell you the chances that a healthy person with or without a family history of a certain disease might develop that disease
- 19. Earliest evidence of hereditarygenetic disorder discovered A B A genetic marker linked to Huntington disease was found on chromosome 4 in 1983, making Huntington disease, or HD, the first genetic disease • Facts… @sources:google images
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