KRM PUBLIC SCHOOL

Block No: 11, Shanthi Nagar, 2nd Lane, Sembium,(Perambur), Chennai, Tamil Nadu -600011

(Affiliated to CBSE, New Delhi, No: 1930658)

Academic Session: 2022 -2023

AISSCE CHEMISTRY
INVESTIGATORY PROJECT

TOPIC: GENETIC DISORDERS

Submitted by:
SAHANNA N.M
Class & Sec: XII M1
Reg. No:

Submitted to:
Mrs. V.Santhana Lakshimi
PGT in Biology
KRM Public School, Perambur, Chennai-11
 KRM PUBLIC SCHOOL
Block No: 11, Shanthi Nagar, 2nd Lane, Sembium,(Perambur), Chennai, Tamil Nadu -600011

(Affiliated to CBSE, New Delhi, No: 1930658)

Certificate

This is to certify that SAHANNA of class X II –M1 has

successfully completed this Biology investigatory
project on “GENETIC DISORDER”

under my guidance and supervision in the academic

year 2022 -2023 as per the guidelines prescribed by the
CBSE under the AISSCE course in the laboratory of this
school.

Signature of internal Signature of external

Examiner Examiner
 ACKNOWLEDGEMENT

In the accomplishment of this project

successfully, many people have best owned
upon me their blessings and the heart
pledged support, this time I am utilizing to
thank all the people who have been
concerned with this project. Primarily I would
thank the almighty for being able to complete
this project with success. Then I would like to
thank Management, Principal Mr. D.P
Sivasakthi Balan and Biology teacher
Mrs.Santhana Lakshimi.V, for their support to
complete this project.
 Index

1. Certificate 11. Autosomal Recessive

2. Acknowledgement 12. X Linked Dominant Disorder

3. Genetic Disorder
13. X Linked Recessive Disorder
4. Causes of Genetic
Disorder
14. Treatment for Genetic Disorder

5. How to identify Genetic

15.Gene Therapy
Disorder

16. Case Study

6. Types of Genetic
Disorder
17.Conclusion
7. Down Syndrome

18. Bibliography
8. Turner Syndrome

9. Klinefelter Syndrome

10.Structural Chromosomal
…….Disorder
GENETIC DISORDERS

INTRODUCTION:

Genes are the building blocks of heredity. They are passed from
parent to child. They hold DNA, the instructions for making proteins.
Proteins do most of the work in cells. They move molecules from one
place to
another, build
structures,
break down
toxins, and do
many other
maintenance
jobs.

Sometimes there is a mutation, a change in a gene or genes. The

mutation changes the gene's instructions for making a protein, so the
protein does not work properly or is missing entirely. This can cause a
medical condition called a genetic disorder.

You can inherit a gene mutation from one or both parents. A

mutation can also happen during your lifetime.
What are the causes of genetic
disorders?

Most of the DNA in our genes instructs the body to make

proteins. These proteins start complex cell interactions that
help you stay healthy.

When a mutation occurs, it affects the genes' protein-

making instructions. There could be missing proteins. Or the
ones you have do not function properly. Environmental
factors (also called mutagens) that could lead to a genetic
mutation include:

• Chemical exposure.

• Radiation exposure.

• Smoking.

• UV exposure from
the sun.
How are genetic disorders
identified?
If you have a family history of a genetic disorder, you may wish to
consider genetic counselling to see if genetic testing is appropriate
for you. Lab tests can typically show whether you have gene
mutations responsible for that condition. In many cases, carrying the
mutation does not always mean you'll end up with it. Genetic
counsellors can explain your risk and if there are steps you can take
to protect your health.

• Carrier testing: This blood

test shows whether you or your
partner carry a mutation linked
to genetic disorders. This is
recommended for everyone
considering pregnancy, even if
there is no family history.

• Prenatal screening: This testing usually involves blood

testing from a pregnant woman
that tells a person how likely it
is that an unborn child could
have a common chromosome
condition.

• Prenatal diagnostic testing:

You can find out whether your
unborn child faces a higher risk
for certain genetic disorders. 0:39 3:38esting uses a sample
of fluid from the womb
Types of Genetic disorders

1. Chromosomal:
This type affects the structures
that hold your genes/DNA within
each cell (chromosomes). With
these conditions, people are
missing or have duplicated
chromosome material.

2. Complex (multifactorial):

These disorders stem from a combination of

gene mutations other factors. This includes
chemical exposure, diet, certain medications
and tobacco or alcohol use.

3.Mendelian disorder
(monogenic):

This group of conditions occurs from a single

gene mutation.

4. Mitochondrial:

It is due to DNA present inside

mitochondria.
1. Chromosomal abnormalities

Chromosomal abnormalities are problems that

affect a chromosome.

Chromosomal abnormalities

Numerical abnormalities Structural abnormalities

• having a missing chromosome • Change in structure of

chromosome

• having an extra chromosome

Chromosomal abnormalities usually occur when there is an error as a

cell is dividing. These errors usually occur within the egg or sperm,
but they can also happen after conception.

It is possible to inherit a chromosomal abnormality from a parent.

However, some develop within a person for the first time.
2. Some Numerical Chromosomal abnormalities

Down Syndrome Trisomy 21

Patau Syndrome Trisomy 13

Edwards Syndrome Trisomy 18

Turner Syndrome Monosomy X

Klinefelter Syndrome 47, XXY

 Down Syndrome

• Down syndrome is a condition in which a person has an

extra chromosome. Chromosomes are small "packages"
of genes in the body. They determine how a baby's body
forms and functions as it grows during pregnancy and
after birth. Typically, a baby is born with 46
chromosomes.

• Babies with Down

syndrome have an extra
copy of one of these
chromosomes,
chromosome 21. A medical
term for having an extra
copy of a chromosome is
'trisomy.'

• Down syndrome is also referred to as Trisomy 21. This

extra copy changes how the baby's body and brain
develop, which can cause both mental and physical
challenges for the baby.

• Even though people with Down syndrome might act and

look similar, each person has different abilities. People
with Down syndrome usually have an IQ (a measure of
intelligence) in the mildly-to-moderately low range and
are slower to speak than other children.
Some common physical features of Down syndrome
include:

• A flattened face, especially the bridge of the nose

• Almond-shaped eyes that slant up

• A short neck

• Small ears

• A tongue that tends to

stick out of the mouth

• Tiny white spots on the iris (coloured part) of the eye

• Small hands and feet

• A single line across the palm of the hand (palmar crease)

• Small Pinky fingers that sometimes

• Poor muscle tone or loose joints

• Shorter in height as children and adults

 Turner Syndrome (Monosomy X)

• A condition that affects only females, results when one

of the X chromosomes (sex chromosomes) is missing or
partially missing. Turner syndrome can cause a variety of
medical and developmental problems, including short
height, failure of the ovaries to develop and heart
defects.

• Turner syndrome may be

diagnosed before birth
(prenatally), du infancy or in
early childhood. Occasionally,
in females with mild signs
and symptoms of Turner
syndrome, the diagnosis is
delaye56 until the teen or young adult years.

• Girls and women with Turner syndrome need ongoing

medical care from a variety of specialists. Regular check-
ups and appropriate care can help most girls and
women lead healthy, independent lives.
SYMPTOMS

Signs and symptoms of Turner syndrome may vary among

girls. For some girls, the presence of Turner syndrome may
not be readily apparent, but in other girls, a number of
physical features and poor growth are apparent early Signs
and symptoms can be subtle, developing slowly over time, or
significant, such as heart defects

• Wide or weblike neck Low-set ears Broad chest with

widely spaced nipples High, narrow roof of the mouth
(palate)

• Arms that turn outward at the elbows

• Fingernails and toenails that are narrow and turned
upward Swelling of the hands and feet, especially at
birth.
• Slightly smaller than
average height at birth
• Slowed growth

• Cardiac defects
• Low hairline at the back
of the head
• Receding or small lower
jaw
• Short fingers and foes in
childhood, teens and
adulthood in childhood
teens and adulthood.
Klinefelter Syndrome (47, XXY)

Klinefelter syndrome (KS) also known as 47, XXY or

XXY, is the set of symptoms that result from two or
more X chromosomes
in males. The primary
features are sterility
and small testicles.
Often symptoms may
be subtle and many
people do not realize
they are affected.
Sometimes symptoms are more prominent and may
include weaker muscles, greater height, poor
coordination, less body hair, breast growth, and less
interest in sex. Often it is on puberty that these
symptoms are noticed Intelligence is usually normal;
however, reading difficulties and problems with speech
a56 more common. Symptoms are typically more
severe if three or more X chromosomes are present.
SYMPTOMS
Fatter around the belly, Clumsier Slower in developing motor
skills, coordination, speed, and muscle strength.

• Puberty for boys with KS usually starts normally but

because their bodies make less testosterone than non-
KS boys, their pubertal Share development may be
disrupted or slow. In addition to being tall, KS boys may
have

• Smaller testes, penis and breast

growth

• Less facial and Body hair, Reduced

muscle tone

• Narrower shoulders and wider

hips Weaker bones, greater risk for
bone fractures

• Decreased sexual interest, reduced

sperm production

An adult male with Klinefelter

Syndrome may have these features:
• Infertility.
Structural Chromosomal Disorder

1.Cri-du-chat Syndrome (Deletion)

Cri-Du-Chat is diagnosed by the obvious symptom of the cat
like cry, most likely after birth in the hospital. The shortened
chromosome 5 may also be seen on a chromosomal analysis.
As well as by noticing more than one physical symptom.

Symptoms:
As an infant the child's cry is
described as sounding like a cat.

●Low birth weight and slow

growth
●Lower ears.
●Partial webbing or fusing of fingers
or toes
●Single line in the palm of the hand
●Slow or incomplete development of
motor skills
●Small head and jaw
●Mental Retardation
 2.Fragile X Syndrome (Duplication)

Fragile X syndrome gets passed from parent to child. A DNA

part called the "CGG triplet repeat" expands within a gene
called FMR1," producing a mutation that causes fragile X
syndrome. A normal part repeats five to 40 times, but in people
with fragile X gene, which messes up the nervous system and
causes the symptoms of fragile X syndrome.

Symptoms (Fragile X Syndrome)

• Learning disabilities.

• Low intelligence quotient (IQ). Their IQ scores decrease with

age.

Delayed early developmental milestones. Milestones are

social/emotional, language/communication, cognitive (thinking,
learning, problem-solving) as well as movement/physical
development (see below).

• Delayed development of nonverbal

communication such as using gestures, body
language and facial expressions.
• Problems with math.
Mendelian disorder (Single gene
disorders)
A single gene disorder is caused by variations (or mutations) in
the DNA sequence of a specific gene. The DNA changes affect
the product that the gene codes
for-usually a protein-causing it
to be altered or missing. The
features of each disorder are
related to the specific gene that
is affected and the job that the
protein has in the body.
Some genetic disorders are so
serious that children who have
them are extremely sick or
cannot survive after birth.
Others are relatively easy to
manage, and with proper care,
people who have them have
very fulfilling lives. The chances
of a good outcome are much
higher if the condition is
identified soon after birth, or
even before.
TYPES OF SINGLE GENE DISORDERS:
DOMINANT RECESSIVE

Autosomal Autosomal Dominant Autosomal Recessive

X-linked X-linked Dominant X-linked Recessive

Autosomal dominant disorder

Autosomal dominant inheritance, in which only one copy of a

defective gene (from either parent) is necessary to cause the
condition:

Early-onset:

• osteogenesis imperfecta

• brittle bone disease

Late onset:

• Huntington disease

• Adult polycystic disease of

the kidney

• Familial cancer syndrome

• Tuberculous sclerosis

• Neurofibromatosis
 i. Autosomal dominant disease

Huntington's disease

• It is found on chromosome 4. This gene provides

instructions for making a protein called
huntingtin.

• Although the function of this protein is

unknown, it appears to play an
important role in nerve cells (neurons)
in the brain.

• People with Huntington's disease

progressively lose muscle control and mental functions
until death

• Symptoms don't usually

appear until around the
age of 20 or later.
 ii.Autosomal recessive disorders

Autosomal recessive inheritance, in which two

copies of a defective gene (one from each parent)
are necessary to cause the condition.

E.g.-haemoglobin disorders, cystic fibrosis,

phenylketonuria and Werdnig Hoffman disease
a. Sickle cell anaemia (Autosomal
recessive)

• Sickle Cell Anaemia is an

inherited disorder that leads to
the production of an abnormal
haemoglobin - haemoglobin S-
(HbS or HgbS). In the red blood
cell (RBC).

• Occur by a mutation in the

Haemoglobin Beta Gene which
can be found in the chromosome 11.

• This disease causes the body to

make abnormally shapes red blood
cells.
• A normal red blood cell is
shaped as a round donut while the
abnormal red blood cell has a "C"
form.
b. Phenylketonuria (PKU) Autosomal
recessive

• It is an autosomal recessive (two copies of an

abnormal gene) genetic disorder characterized by a
deficiency in the hepatic enzyme phenylalanine
hydroxylase (PAH).

• Necessary to metabolize the amino acid

phenylalanine to the amino acid tyrosine.

• When PAH is deficient,

phenylalanine accumulates and
is converted into phenyl pyruvic
acid, phenyl- lactic acid and
phenyl - acetic acid (also known
as phenyl ketone), which is
detected in the urine.

• Elevated blood phenylalanine and detection of

phenyl ketones in the urine is diagnostic.
 ii.X linked Dominant disorders

• Dominant X-linked mutations are rare.

•Affects either sex, but more females than males

•Inheritance of mutant X - will get the disease

•Females are more mildly

and more variably affected
than males

• The child of an affected

female regardless of its sex
has a 50% chance of being
affected

For an affected male, all of his daughters but none of

his sons will be affected.

Examples

• Incontinentia
Pigmenti
 • Hypophosphatemic Rickets
• Charcot-Marie-Tooth disease

• Chondrodysplasia Punctataiv.X Linked Recessive

Disorders

iv. X Linked Recessive Disorder

Responsible gene on X chromosome:

For females, both copies of the X chromosome must be

affected.

Males, hemizygous for the X chromosome, much more

likely to be affected.

Examples

■ Haemophilia A and B

■Glucose-6-phosphate
dehydrogenase deficiency

■ Colour blindness

Bruton agammaglobulinemia

■Wescott-Aldrich syndrome
■Chronic granulomatous disease

■Diabetes insipidus

a. Haemophilia (X linked Recessive)

■ Haemophilia is a hereditary disease caused by deficiencies

in coagulation factors VIII (haemophilia A) and IX
(haemophilia B) due to mutations of the F8 and F9 genes on
the X chromosome.

■ Deletion and insertion

mutations and mutations that
cause premature termination of
synthesis usually cause severe
disease. Certain missense
mutations also can lead to severe haemophilia.

Haemophilia A: ■ Abnormality of factor VIII

■ X-Linked Recessive

Haemophilia B: ■ Disturbance in factor IX

■ X-Linked Recessive
Colour-blindness (X linked
Recessive)

• Red/Green or Blue
colour blindness is
passed down from
parents.

• The gene responsible is on X

chromosome.

• Mutations capable of causing colour blindness

originate from at least 19 different chromosomes
and many different genes.

• More males are affected the females are

basically carrier.
TREATMENT FOR GENETIC DISORDERS

There is no permanent treatment for genetic disorder.

But with regular medical practices and medications,

the severity of these genetic disorders can be

controlled. Few diseases and their treatment to be

followed are:

Down syndrome / Treatments

Treatment consists of therapy and self-care

Early intervention programmes with a team of therapists and special

educators who can treat each child's specific situation are helpful in
managing Down's syndrome.

Self-care
Physical exercise and Special education

Therapies
Support group, Speech therapy, Occupational Therapy and Physical
Therapy

Devices
Glasses
Haemophilia / Treatments

Treatment consists of medications to improve blood

clotting
Treatment includes injections of a clotting factor or plasma.

Medications
Clotting promoter

Sickle cell anaemia / Treatments

Treatment depends on severity

Treatments include medication, blood transfusions and

rarely a bone-marrow transplant.

Devices

Patient-controlled analgesia

Medications

Narcotic, Chemotherapy, Vitamin and Blood transfusion

Huntington's disease/ Treatments

Self-care
 • Postural drainage

• Medical procedure

• Chest wall oscillation

•

Recent developments in scientific world have led

to the treatment of genetic disorders by
Gene Therapy.

Recent
advancement
and
continuous
ongoing
projects in
gene therapy has seen wide improvements in patients.
Even though complete cure
has not been possible
patients are definitely
benefitted by this process.
Real Case Studies

CASE STUDY 1
7-year-old Sophie Green, who was born without arms

This 7-year-old girl was born without her arms but that
has not stopped her from having a positive outlook on
life. She taught herself how to do all of her daily jobs
using only her feet, such as eating, drawing and
writing.

One of her favourite things

to do is dancing while her
brother plays the piano,
though she admits that
keeping her balance is a
challenge. Her parents
believe that with her upbeat
and optimistic attitude, she
can achieve anything in life.
Keeping a positive
attitude, whenever someone asks her, "Where are
your arms?" her usual reply is "I buried them!"
CASE STUDY 2:

12-year-old twins Stevie and Eddie, who are eternally

hungry

Stevie and Eddie, who suffer from Prader-Will

syndrome, lead a very difficult and strict lifestyle. Their
condition leads to reduced hormone production in
their bodies which makes them hungry every moment
of each day.

Their mother has to lock

up the pantry,
refrigerator and even
the garbage each night
as the twins tend to
have an overwhelming
appetite and will even
eat the food lying on the
floor. The excessive
eating has led to obesity and even nosebleeds and
muscle cramps.

Even after this, the twins have started following a strict

fitness regime and only have an intake of 1200 calories
a day in order to healthy
CASE STUDY 3:

30-year-old Challi looks twice her age

Challi was diagnosed with Progeria, which makes

her look 60 even though she is only 30. Even
though people with this condition only live up to
the age of 15, she has made it all the way to 30
and recently got married.

Being bullied and teased in middle school only

made her stronger as a person. She never let the
treatments and medication break her spirit
CONCLUSION:

Genetic disorders are caused due to mutations in DNA.

This mutation affects the chromosomes leading to
various disorders. We know many disorders till date
and many more new disorders have been found in new
borns in recent time. Permanent cure is not available
as such but many techniques have been recently
developed including Gene Therapy for reducing the
abnormalities. Mutations can be diagnosed at the
foetal level and treated accordingly which otherwise
could be life threatening. Treatments tend to focus to
prevent complications and to improve quality of life.

BIBLIOGRAPHY:

o Molecular diagnosis and genetic diseases.

o Thompson & Thompson …Genetic medicine.
o Encyclopaedia…. Genetic disorders and birth
defects
o Google search
o Wikipedia