medical genetics chromosomal disorders.pdf

1. Human genetic disorders
encompass a wide range of
conditions caused by
variations in our DNA. These
variations can be small
changes in individual genes or
more complex chromosomal
abnormalities. While some
genetic disorders are rare,
others are quite common,
affecting millions of people
worldwide.
Midical genetic chromosoal disorders 1

2. chromosomal abnormalities
single-gene disorders
or
multifactorial disorders
Midical genetic chromosoal disorders 2

3. chromosomal abnormalities
are a fascinating and complex area
of human genetics
types of chromosomal abnormalities:
• Numerical abnormalities: These
involve having an incorrect number of
chromosomes, most commonly extra
or missing copies. Examples include
Trisomy 21 (Down syndrome) and
Turner syndrome (missing an X
chromosome).
• Structural abnormalities: These involve
changes in the structure of individual
chromosomes, such as deletions,
duplications, inversions, or
translocations.
• Mosaicism: This occurs when an
individual has a mixture of cells with
different chromosomal complements.
Midical genetic chromosoal disorders 3

4. Causes of chromosomal
abnormalities:
1. Errors during cell division
(mitosis or meiosis): Mistakes
during chromosome separation
can lead to abnormal numbers
or structures.
2. Advanced maternal or paternal
age: The risk of certain
chromosomal abnormalities
increases with age, particularly
for mothers.
3. Genetic factors: In some cases,
certain genes may increase the
risk of chromosomal
abnormalities.
Midical genetic chromosoal disorders 4

5. 1. Effects of chromosomal
abnormalities:
2. Impact on physical
development and health: Many
chromosomal abnormalities
have associated physical
features, health complications,
and developmental delays.
3. Intellectual and cognitive
abilities: Some abnormalities
can affect cognitive function
and learning.
4. Social and emotional well-
being: Individuals with
chromosomal abnormalities
may face additional challenges
in adapting to life and
navigating social interactions.
Midical genetic chromosoal disorders 5

6. Diagnosis and management:
1. Prenatal screening and
testing: Various tests can be done
during pregnancy to detect
chromosomal abnormalities in the
developing fetus.
2. Postnatal diagnosis: Chromosomal
abnormalities can also be diagnosed
after birth through blood tests and
karyotyping (analyzing chromosome
number and structure).
3. Management: There is no cure for
chromosomal abnormalities, but
various therapies and interventions
can help manage symptoms and
improve quality of life
Midical genetic chromosoal disorders 6

7. 1. Conditions characterized by an extra
chromosome, like trisomy 21 (Down
syndrome)?
2. Conditions arising from missing
chromosomes, like Turner syndrome
(missing X chromosome)?
3. Disorders caused by structural
abnormalities, such as deletions,
duplications, or translocations?
4. Specific syndromes associated with
chromosomal abnormalities, like
Klinefelter syndrome (extra X
chromosome in males) or Cri du Chat
syndrome (deletion on chromosome
5)?
Midical genetic chromosoal disorders 7

8. Down Syndrome (Trisomy 21)
Down syndrome, also known as
trisomy 21, is a genetic condition
caused by the presence of an extra
copy of chromosome 21. Typically,
humans have 46 chromosomes,
arranged in 23 pairs. In Down
syndrome, individuals have 47
chromosomes, with the extra copy
being chromosome 21.
Midical genetic chromosoal disorders 8

9. the extra chromosome 21 in Down
syndrome can occur in three ways:
1. Nondisjunction: During cell
division, chromosomes fail to
separate properly, resulting in
one cell having an extra copy of
chromosome 21.
2. Translocation: A piece of
chromosome 21 breaks off and
attaches to another
chromosome.
3. Mosaicism: This is a less
common form where only
some cells in the body have an
extra copy of chromosome 21.
Midical genetic chromosoal disorders 9

10. Symptoms:
Down syndrome can cause a wide range of physical
and intellectual disabilities, varying in severity from
person to person. Some common symptoms include:
1. Facial features: Small eyes, flat bridge of the nose,
upturned eyes, small ears, and a short neck.
2. Developmental delays: Delayed speech and
language development, motor skills, and cognitive
abilities.
3. Learning disabilities: Difficulty with reading,
writing, and math.
4. Health problems: Increased risk of heart defects,
vision and hearing problems, thyroid problems,
and other medical conditions.
Midical genetic chromosoal disorders 10

11. Diagnosis:
Down syndrome can be
diagnosed before birth
through prenatal screening
tests, such as amniocentesis
or chorionic villus sampling.
After birth, it can be
diagnosed through a physical
exam and a blood test called a
karyotype.
Midical genetic chromosoal disorders 11

12. Treatment:
There is no cure for Down syndrome, but early
intervention and therapy can help individuals
reach their full potential. This may include
speech therapy, occupational therapy, physical
therapy, and educational support.
Midical genetic chromosoal disorders 12

13. Living with Down Syndrome:
Many individuals with Down
syndrome live full and
productive lives. They can
participate in school, work,
and community activities.
With support and
encouragement, they can
achieve their goals and live
fulfilling lives.
Midical genetic chromosoal disorders 13

14. Turner Syndrome (Missing X
Chromosome)
Turner syndrome is a genetic
condition that affects females and
occurs when one of the X
chromosomes is missing or
partially missing. Typically, females
have two X chromosomes (XX),
while males have one X and one Y
chromosome (XY). In Turner
syndrome, individuals have only
one X chromosome (X0) or a
mosaic of cells with some cells
having one X chromosome and
others having two X chromosomes
or no X chromosomes.
Midical genetic chromosoal disorders 14

15. Causes:
The missing or partially
missing X chromosome in
Turner syndrome is caused by
errors during cell division.
These errors can occur during
the formation of eggs or
sperm, or during the early
development of the embryo.
Symptoms:
Midical genetic chromosoal disorders 15

16. Symptoms:
Turner syndrome can cause a wide range of symptoms, varying in severity
from person to person. Some common symptoms include:
1. Short stature: Most individuals with Turner syndrome are shorter than
average.
2. Delayed puberty: Individuals with Turner syndrome may not go through
puberty at all, or they may experience a delayed or incomplete puberty.
3. Infertility: Due to the lack of ovaries or the presence of underdeveloped
ovaries, most individuals with Turner syndrome are infertile.
4. Learning disabilities: Some individuals with Turner syndrome may have
learning disabilities, such as difficulty with math or reading.
5. Heart defects: Individuals with Turner syndrome have an increased risk
of certain heart defects.
6. Kidney problems: Some individuals with Turner syndrome may have
kidney problems.
7. Vision problems: Some individuals with Turner syndrome may have
vision problems, such as nearsightedness.
Midical genetic chromosoal disorders 16

17. Diagnosis:
Turner syndrome can be
diagnosed before birth
through prenatal screening
tests, such as amniocentesis
or chorionic villus sampling.
After birth, it can be
diagnosed through a physical
exam and a blood test called a
karyotype.
Midical genetic chromosoal disorders 17

18. Living with Turner
Syndrome:
Many individuals with
Turner syndrome live full
and productive lives. They
can participate in school,
work, and community
activities. With support
and treatment, they can
achieve their goals and
live fulfilling lives.
Midical genetic chromosoal disorders 18

19. treatment:
There is no cure for Turner syndrome, but
treatment can help manage the symptoms
and improve quality of life. Treatment
may include:
1. Growth hormone therapy: This can
help individuals with Turner
syndrome reach their full potential
height.
2. Hormone replacement therapy: This
can help individuals with Turner
syndrome develop secondary sexual
characteristics and prevent
osteoporosis.
3. Fertility treatments: In some cases,
individuals with Turner syndrome
may be able to become pregnant
using donor eggs and IVF.
4. Support services: Individuals with
Turner syndrome may benefit from
support groups and counseling.
Midical genetic chromosoal disorders 19

20. Klinefelter syndrome (XXY)
Causes and Genetics:
•Nondisjunction: The most
common cause, where during cell
division, chromosomes fail to
separate properly, resulting in an
egg or sperm with an extra X
chromosome.
•Mosaicism: Less frequent, where
some cells have 47 chromosomes
(XXY) and others have the typical
46 chromosomes (XY).
•Translocation: A rare occurrence
where part of the X chromosome
attaches to another chromosome.
Midical genetic chromosoal disorders 20

21. impact on Development:
Extra X chromosome affects
production of testosterone, leading
to delayed puberty, small testes,
and infertility.
Development of male secondary
sexual characteristics may be
limited.
Increased risk of certain medical
conditions like breast cancer,
hypogonadism, and metabolic
issues.
Cognitive and learning challenges
can occur, including difficulties
with language, math, and social
skills.
Midical genetic chromosoal disorders 21

22. Symptoms and Features:
1. Physical: Taller than average
height, slender build, small
testes, gynecomastia (enlarged
breast tissue), reduced facial
hair, and delayed puberty.
2. Cognitive: Learning difficulties,
speech and language delays,
difficulties with executive
function, attention, and
memory.
3. Social: Social anxiety, low self-
esteem, difficulties with social
interaction and
communication.
Midical genetic chromosoal disorders 22

23. Diagnosis and Testing:
•Prenatal screening: Amniocentesis
or chorionic villus sampling to
analyze fetal chromosomes.
•Newborn screening: Karyotype
analysis performed through a
blood test at birth.
•Later diagnosis: Blood test and
physical examination, possibly
followed by genetic testing, in
cases of delayed puberty or other
symptoms.
Midical genetic chromosoal disorders 23

24. treatment and Management:
•Testosterone replacement
therapy: Improves development of
secondary sexual characteristics,
promotes muscle growth, and
prevents bone loss.
•Speech and language
therapy: Helps with
communication and language skills.
•Educational
support: Individualized educational
plans and learning strategies to
address cognitive challenges.
•Social and emotional
support: Counseling and support
groups can help individuals cope
with challenges and build self-
esteem Midical genetic chromosoal disorders 24

25. Living with Klinefelter Syndrome:
•Many individuals with XXY live
fulfilling lives with proper
diagnosis, treatment, and support.
•Challenges can be managed
through therapy, education, and
social support.
•Advocacy groups and resources
are available to provide
information, connect individuals
with the community, and support
research efforts.
Midical genetic chromosoal disorders 25

26. Midical genetic chromosoal disorders 26