09/24/2017

GENETICS mci-screeningt-test-and-indian-medical-examz-high-yield-important-topics-study-method/

By Live Dr - Wed Feb 11, 2:42 am

GENETICS

AUTOSOMAL DOMINANT DISORDERS AUTOSOMAL RECESSIVE DISORDERS
Hereditary nonpolyposis colon cancer

Familial hypercholesterolemia

Familial adenomatous polyposis

Von Hipple Landau syndrome

MEN type 1 and 2

Retinoblastoma

Spherocytosis

Antithrombin III and factor V Leiden

Von Willebrand’s disease

Hypertrophic obstructive cardiomyopathy

Polycystic kidney disease

Hereditary hemorrhagic disorders

Achondroplasia

Marfan’s syndrome

Amyloidosis

Cystic fibrosis

Alpha-1 antitrypsin deficiency

Ataxia telengiectasia

Alpha and beta Thalassemia

Sickle cell disease

Hereditary spherocytosis

Wilson’s disease

Hemochromatosis

Phenylketonuria

Gaucher’s disease

Niemann Pick disease

Tay Sachs disease

MPS I-VII

Glycogen storage disorders I-VIII

Congenital adrenal hyperplasia

X LINKED DOMINANT DISORDERS
Vitamin D resistant rickets

Orofacial digital syndrome

Incontinentia pigmneti

Mitochondrial disorders
Keans Sayre syndrome

Mitochondrial myopathy

MELAS

Leber’s hereditary optic neuropathy

Myoclonic epilepsy (Ragged red fibres syndrome)

Pearson syndrome

Traits inherited along y chromosome
Male infertility

Gonadoblastoma

QUOTE CORNER

A goal is not always meant to be reached, it often serves simply as something to aim at.- Bruce Lee

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CHROMOSOMAL BREAKAGE DISORDERS
Fanconi’s syndrome

Bloom’s syndrome

Ataxia telengiectasia

Nijmegen breakage syndrome

(Berlin breakage syndrome /

Seemanova syndrome)

CONGENITAL ADRENAL HYPERPLASIA FEMALE MALE
21 b hydroxylase deficiency

(most common)

Virilisation Precocious puberty
11 b hydroxylase deficiency Virilisation Precocious puberty
17 a hydroxylase Primary amenorrhoea Pseudohermaphradoitism

MUTATIONS

Silent mutation Codon containing the changed base codes for the same amino acid
Missense mutation Codon containing the changed base codes for a different amino acid

this mistaken codon may be acceptable, partially acceptable or unacceptable to functioning of that protein molecule

Non sense mutation Codon  containing the changed base becomes the termination codon

consanguinity

1st degree Incest
2nd degree Uncle-niece

Aunt-nephew

3rd degree Cousins

*Regular Trisomy 21 is found in 94 % cases of Down syndrome

1 % are mosaics

5% are due to translocation

*Achondroplasia

Most common disproportionate dwarfism

Trident hand- index and ring finger are divergent

TRIVIAL TRUTH

Dolly, a Finn Dorsett ewe, was the first mammal to have been successfully cloned from an adult cell. She was born after 277 eggs were used to create 29 embryos, which only produced three lambs at birth, only one of which lived.

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*Ataxia telengiectasia

Autosomal recessive

Basic defect in abnormal sensitivity to X rays and certain radiomimetic chemicals which leads to chromosome and chromatid breakage

*Fragile X syndrome is the second most common cause of mental retardation after Down syndrome in males

*Sherman’s paradox-

Brothers of transmitting males have lesser risk of having mental retardation as compared to grandson of transmitting males.

Seen in fragile X syndrome

*Pseudo gene is a region of DNA that shows extensive similarity to a known gene, but which cannot itself function, either because it has lost the signal transduction for transcription or because it carries mutations that prevent it from being translated into protein

*Marfan’s syndrome is associated with mutation in fibrillin protein

*G6 PD deficiency is X-linked recessive transmission

*Angelman Syndrome is characterised by intellectual and developmental delay, speech impediment, sleep disturbance, unstable jerky gait, seizures, hand flapping movements, frequent laughter/smiling and usually a happy demeanour. It is a classic example of genetic imprinting caused by deletion or inactivation of critical genes on the maternally inherited chromosome 15. The sister syndrome is called Prader-Willi syndrome, and is caused by paternal genes.

An older, alternative term for AS is happy puppet syndrome.

FEATURES OF DOWNS SYNDROME
Oblique eye fissures with epicanthic skin folds on the inner corner of the eyes

Muscle hypotonia

A flat nasal bridge

A single palmar fold (Simian crease)

A protruding tongue

A short neck

White spots on the iris known as Brushfield spots

Excessive space between large toe and second toe

A single flexion furrow of the fifth finger

A higher number of ulnar loop dermatoglyphs

QUOTE CORNER

Patience, persistence and perspiration make an unbeatable combination for success.

Napoleon Hill.

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