GENETIC DISORDERS

WHAT IS

GENETICS?

Genetics is a field in biology

and is the science of genes,

traits and variations in

organisms.

Take a look!!!

THESE ARE SOME OF THE GENETIC DISORDERS

MUTATIONA mutation is the change in the genetic element of an organism.It can result in the change in genotype and phenotype of an organism.

Causes of Mutations• A Mutation occurs

when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene

• A Mutagen is an agent of substance that can bring about a permanent alteration to the physical composition of a DNA gene such that the genetic message is changed

MUTATION

POINT MUTATION

CHROMOSOMAL MUTATION

POINT MUTATION

A point mutation, or single base substitution, is a type of mutation that causes the replacement of a single base nucleotide with another nucleotide of the genetic material, DNA or RNA. The term point mutation also includes insertions or deletions of a single base pair.

Types of point mutations

CHROMOSOMAL MUTATION

A mutation involving a long segment of DNA. These mutations can involve deletions, insertions, or inversions of sections of DNA. In some cases, deleted sections may attach to other chromosomes.

CHROMOSOMAL MUTATION

NUMBER OF CHROMOSOME

STRUCTURE OF CHROMOSOME

a. Numbers of sets of chromosomes with respect to whole genome-polyploidy.

b. Numbers of a particular chromosomes e.g. chromosome.

Alterations in chromosome number

Changes in Chromosome Structure

The pairing of homologous chromosomes during prophase I of meiosis can lead to a number of errors. Miss-pairings can result in duplication or deletion of entire sections of chromosomes or inversions of sections so that the order of a DNA sequence is reversed with respect to the rest of the chromosome.

CHANGE IN STRUCTURE OF CHROMOSOMES

DELETION

INVERSION DUPLICATIONTRANSLOCA

TION

deletion (1) duplication (2) inversion (3).

Change in structure of chromosomes

M A N H A S C A T

M A H A S C A T M

M A N H A S C A T

M A N N H A S C A

DELETION DUPLICATION

M A N H A S C A T M A N H A S C A T

M A H N A S C A T M A N Z A S C A T

INVERSION TRANSLOCATION

GENETIC DISORDERS

CHROMOSOMAL DISORDERS MENDELIAN DISORDERS

CHROMOSOMAL DISORDER

Chromosomal disorders is the disorder which caused due to the absence or

excess or abnormal arrangement of one or more chromosomes. Failure of

segregation of chromatids during cell division cycle results in the gain or less of

a chromosome.

DOWN’S SYNDROME

Down's syndrome, also known as trisomy 21,

is a genetic disorder caused by the presence

of all or part of a third copy of chromosome

21. It is typically associated with physical

growth delays, characteristic facial features

and mild to moderate intellectual disabilities.

The average IQ of a young adult with Down

syndrome is 50, equivalent to the mental age

of an 8 or 9 year old child.

KLIENFELTER’S SYNDROME

This is caused by additional copy of chromosome number 21. The affected individual is short statured with small

round head, furrowed tongue and partially open mouth.

Turner syndrome is a chromosomal disorder that affects only females. It is characterized by the absence of part or all of a second sex chromosome in some or all cells. Approximately 1 in every 2,500 to 3,000 girls is born with the condition.

Mendelian disorder are mainly determined by alteration or mutation in the single gene. These disorders are transmitted to

the offspring. The mutation can either occur on a single chromosome or on a pair of homologous chromosomes. At present, more than 5000 Mendelian disorders have been

identified in human.

This sex linked recessive disease, which shows its transmission from unaffected carrier female to some other male progeny. In this disease a single protein that is a part of the cascade of proteins involved in the clotting of blood is affected due to this in an affected individual a simple cut will result in non stop bleeding.

HAEMOPHILLIA

PHENYLKETONEURIAPhenylketonuria (PKU) is a rare inherited condition in which there is a build up of phenylalanine hydroxylase in the body. Untreated PKU can lead to intellectual disability, seizures, and other serious medical problems.

Mutation

Point mutation Chromosomal Mutation

Change in number

Change in structure

Deletion

Inversion

Duplication

Translocation

Genetic disorder

Chromosomal disorder

Down syndrome

Klienfelter’s syndrome

Turner syndrome

Mendelian disorder

Haemophillia

Phenylketonuria