Genetics for UG

GENETICS:

GENETICS Dr. Muhammedirfan H. Momin Assistant Professor Community Medicine Department, Government Medical College, Surat.

Autosomal Dominant:

Autosomal Dominant

Autosomal Dominant Disorder:

Autosomal Dominant Disorder Males and females are affected in equal frequencies. Probability that an offspring (of heterozygotes)will be affected is 50%. Disease does not occur in the offspring of unaffected individuals. Show great variability in manifestation. ‘Incomplete penetrance’ seen( showing ‘skipped’ in a generation). Generally milder than recessive disorders .

Examples of Autosomal Dominant Disorders:

Examples of Autosomal Dominant Disorders Achondroplasia Acute Intermittent Porphyria Adult Polycystic Disease Alzheimer’s Disease (familial). Alpha1 Antitrypsin Deficiency C1 esterase inhibitor deficiency Criggler Najjar Syndrome II Hereditary Elliptocytosis Hereditary Spherocytosis Huntington’s Chorea Marfans Disease Dystrophia myotonica Neurofibromatosis Osteogenesis imperfecta(some forms) Peutz Jegher’s Syndrome Rotors Syndrome Tuberose sclerosis Von Willebrand’s disease.

Autosomal Recessive:

Autosomal Recessive

Autosomal Recessive Disorders:

Autosomal Recessive Disorders Manifest only in homozygous state. Affected individual is generally offspring of heterozygous parents. 25% chances that offspring have Normal Phenotype,50% probability of heterozygous, 25% risk of homozygous for recessive alleles. More common in consanguineous marriages-Jews & Parses. Clinical features usually severe.

Examples of Autosomal Recessive Disorders:

Examples of Autosomal Recessive Disorders Albinism(Oculocutaneous) Ataxia telangiectasia. Criggler Najjar Syndrome I Cystic fibrosis Dubin Johnson Syndrome Epidermolysis bullosa(some) Fanconi’s Syndrome Friedreich’s Ataxia Galactosemia Gauchars Disease Wilson Disease Glycogen storage Disease Hereditary Hemochromatosis Hurlers Syndrome Homocystinuria Infantile polycystic kidney disease Laurence Moon Biedl Syndrome Phenylketoneurea Sickle cell disease Tay Sachs Disease Beta Thallesemia

X Linked Dominant:

X Linked Dominant

X-Linked Dominant Disorder:

X-Linked Dominant Disorder Rare disorders Both Heterozygous females and hemizygous males are affected. All sons of affected male Normal, all daughters affected. Affected females transmit the disease to half of the sons and half of the daughters. More severe in males. Examples-Vitamin D resistant Rickets (Hypophosphatemia type) ,Oro facio digital Syndrome, Incontinentia pigmenti

X Linked Recessive:

X Linked Recessive

X-Linked Recessive Disorder:

X-Linked Recessive Disorder Usually present in males and present in homozygous females. Transmitted by healthy female carrier or affected males if they survive to reproduce .

Examples of X-Linked Recessive Disorders:

Examples of X-Linked Recessive Disorders Albinism (Ocular) Becker’s muscular dystrophy Christmas Disease Color Blindness Duchene muscular dystrophy Fabry’s Disease Fragile X Chromosome G6PD Deficiency Hemophilia A Hunters Syndrome Lesch Nyhan Syndrome Menkes Syndrome Mental retardation ( with or with out fragile site) Nephrogenic Diabetes insipidus Red Green Color blindness Wiskott Aldrich Syndrome.