3. OBJECTIVES
At the end of this session everyone should able to:-
• Explain the genetic condition affect adolescent and
adults.
• Identify characteristics of genetic conditions
• Determine genetic change of the conditions
(disorder)
• Explain inheritance pattern of the conditions
4. Introduction
• A genetic condition (disorder) is a disease that is
caused by an abnormality in an individual's DNA.
Abnormalities can be as small as a single-base
mutation in just one gene, or they can involve the
addition or subtraction of entire chromosomes.
• Genetic conditions can be diagnosed by either on
the basis of a person's physical characteristics and
family history, or on the results of a screening test.
5. GENETIC CONDITION OF ADOLESCENTS
1. Adolescent Idiopathic Scoliosis
• Adolescent idiopathic scoliosis is an abnormal
curvature of the spine that appears in late childhood or
adolescence. Instead of growing straight, the spine
develops a side-to-side curvature, usually in
an elongated "S" or "C" shape; the bones of the spine
are also slightly twisted or rotated.
6.
7. • For unknown reasons, severe and progressive curves
occur more frequently in girls than in boys.
• However, mild spinal curvature is equally common in
girls and boys.
• Scoliosis classified into mild scoliosis and severe
scoliosis where by mild scoliosis does not cause pain,
problems with movement, or difficulty breathing. It
may only be diagnosed if it is noticed during a regular
physical examination or a scoliosis screening at school.
8. Characteristics
• The most common signs of the condition include:-
• Tilt or unevenness (asymmetry) in the shoulders,
hips, or waist.
• Having one leg that appears longer than the other.
• A small percentage of affected adolescents develop
more severe, pronounced spinal curvature.
9.
10.
11. Frequency
• Adolescent idiopathic scoliosis is the most common
spinal abnormality in late children. It affects an
estimated 2 to 3 percent of children in the U.S.
Genetic changes
• AIS results from a combination of genetic and
environmental factors.
• Also the abnormal spinal curvature may be related to
hormonal problems, abnormal bone or muscle growth
and nervous system abnormalities.
12. Inheritance pattern
• Adolescent idiopathic scoliosis can be sporadic,
which means it occurs in people without a family
history of the condition, sometimes it can cluster in
the families.
13. 2. Juvenile Myoclonic Epilepsy
• Juvenile myoclonic epilepsy is a condition
characterized by recurrent seizures (epilepsy). This
condition begins in childhood or adolescence,
usually between ages 12 and 18, and lasts into
adulthood.
• The most common type of seizure in people with
this condition is myoclonic seizures, which cause
rapid, uncontrolled muscle jerks.
14. Characteristics
• People with this condition may have:-
• Generalized tonic-clonic seizures (also known as
grand mal seizures), which cause
– Muscle rigidity
– Convulsions
– Loss of consciousness.
• Seizures can be triggered by a lack of sleep, extreme
tiredness, stress, or alcohol consumption.
15. Frequency
• Juvenile myoclonic epilepsy affects an estimated 1
in 1,000 people worldwide. Approximately 5
percent of people with epilepsy have juvenile
myoclonic epilepsy.
16. Genetics changes
• The genetics of juvenile myoclonic epilepsy are
complex and not completely understood.
• Mutations of GABRA1 and EFHC1 genes can cause
or increase susceptibility to this condition.
• Mutation of these two genes causes an increase in
the number of neurons and disrupts the chlorine
and calcium balance which results in
overstimulation of neurons and trigger seizures.
17. Inheritance pattern
• Inherited in an autosomal dominant pattern, which
means one copy of the altered gene in each cell is
sufficient to cause the disorder.
• Although juvenile myoclonic epilepsy can run in
families, many cases occur in people with no family
history of the disorder.
18.
19. 3. Leydig Cell Hypoplasia
• This is a condition that affects male sexual
development
• Leydig cells is a cell which secrete male sex hormones
(androgens) that are important for normal male sexual
development before birth and during puberty.
• In Leydig cell hypoplasia, affected individuals with a
typical male chromosomal pattern (46, XY) may have a
range of genital abnormalities.
20. Characteristics
• Underdeveloped Leydig cells
• Very low serum testosterone
• High leuteinizing hormone level
• Small penis
• Hypospadias
• Hypogonadism
• Androgen deficiency
21. • Female phenotype
• Blind ending vagina
• Primary amenorrhea
• Lack of secondary sex differentiation during puberty
• Fertility problems
• Female external genitalia
22. Frequency
• Leydig cell hypoplasia is a rare disorder; its
prevalence is unknown.
Genetic Changes
• Mutations in the LHCGR gene cause Leydig cell
hypoplasia. The LHCGR gene mutations that cause
Leydig cell hypoplasia poor developed or absent
Leydig cells and impaired production of
testosterone.
23. Inheritance Pattern
• This condition is inherited in an autosomal recessive
pattern, which means both copies of the gene in
each cell have mutations.
• The parents of an individual with an autosomal
recessive condition each carry one copy of the
mutated gene, but they typically do not show signs
and symptoms of the condition.
24.
25. GENETICS CONDITIONS OF ADULTS
1. Parkinson disease
• This is a progressive disorder of the nervous system.
The disorder affects several regions of the brain,
especially an area called the substantia nigra that
controls balance and movement.
• Generally, Parkinson disease that begins after age 50 is
called late-onset disease. The condition is described as
early-onset disease if signs and symptoms begin before
age 50.
26.
27. Characteristics of Parkinson disease
• Trembling or shaking (tremor) of a limb. Typically, the
tremor begins on one side of the body, usually in one
hand. Tremors can also affect the arms, legs, feet, and
face.
• Rigidity or stiffness of the limbs and torso,
• Slow movement (bradykinesia) or an inability to move
(akinesia),
• Impaired balance and coordination (postural instability).
• These symptoms worsen slowly over time.
28.
29.
30. Frequency
• Parkinson disease affects more than 1 million
people in North America and more than 4 million
people worldwide. In the United States, Parkinson
disease occurs in approximately 13 per 100,000
people, and about 60,000 new cases are identified
each year.
31. Genetic changes
• Most cases of Parkinson disease probably result from a
complex interaction of environmental and genetic factors.
• Familial cases of Parkinson disease can be caused by
mutations in the LRRK2, PARK2, PARK7, PINK1, or SNCA
gene.
• This influence the risk of developing the disorder.
• Many Parkinson disease symptoms occur when nerve cells
(neurons) in the substantia nigra die or become impaired.
32. Inheritance Pattern
• Most cases of Parkinson disease occur in people
with no apparent family history of the disorder.
These sporadic cases may not be inherited, or they
may have an inheritance pattern that is unknown.
33.
34.
35. 2. Alzheimer disease
• Alzheimer disease is a degenerative disease of the
brain that causes dementia, which is a gradual loss
of memory, judgment, and ability to function. This
disorder usually appears in people older than age
65, but less common forms of the disease appear
earlier in adulthood.
36.
37.
38. Characteristics of Alzheimer’s disease include:
• Changes in personality
• Impaired gait or movement
• Language difficulties
• Low energy
• Memory loss
• Mood swings
• Problems with attention and orientation
• Problems with simple mathematical tasks
39. Frequency
• Alzheimer disease currently affects an estimated 2.4
million to 4.5 million Americans. Because the risk of
developing Alzheimer disease increases with age
and more people are living longer, the number of
people with this disease is expected to increase
significantly in coming decades.
40. Genetic changes
• Most cases of early-onset Alzheimer disease are caused
by gene mutations that can be passed from parent to
child. This form of the disorder can result from
mutations in one of three genes: APP, PSEN1, or PSEN2.
mutations of these genes build a toxic (amyloid beta
peptide and amyloid plaques) may lead to the death of
nerve cells.
• Also people with Down syndrome have an increased
risk of developing Alzheimer disease.
41. Inheritance Pattern
• The early-onset form of Alzheimer disease is
inherited in an autosomal dominant pattern, which
means one copy of the altered gene in each cell is
sufficient to cause the disorder. In most cases, an
affected person inherits the altered gene from one
affected parent.
42.
43. 3. Hereditary hemochromatosis (Ferroportin disease)
• Hereditary hemochromatosis is a disorder that causes
the body to absorb too much iron from the diet.
• The excess iron is stored in the body's tissues and
organs, particularly the skin, heart, liver, pancreas, and
joints.
• Because humans cannot increase the excretion of iron,
excess iron can overload and eventually damage tissues
and organs.
• For this reason, hereditary hemochromatosis is also
called an Iron overload disorder.
44.
45. Characteristics
Early symptoms of hereditary hemochromatosis are
nonspecific and may include:-
• Fatigue
• Joint pain
• Abdominal pain
• Loss of sex drive.
46. Later signs and symptoms can include:-
• Arthritis
• Liver disease
• Diabetes
• Heart abnormalities,
• Skin discoloration.
47. Frequency
• This is common genetic disorders in the United
States, affecting about 1 million people. It most
often affects people of Northern European descent.
Also hemochromatosis is considered rare and has
been studied in only a small number of families
worldwide.
48. Genetic Changes
• Mutations in the HAMP, HFE, HFE2, SLC40A1, and
TFR2 genes cause hereditary hemochromatosis.
• Mutations in any of these genes impair the control
of iron absorption during digestion and alter the
distribution of iron to other parts of the body. As a
result, iron accumulates in tissues and organs,
which can disrupt their normal functions.
49. Inheritance Pattern
• This is inherited in an autosomal recessive pattern,
which means both copies of the gene in each cell
have mutations. Most often, the parents of an
individual with an autosomal recessive condition
each carry one copy of the mutated gene but do not
show signs and symptoms of the condition.
• But sometimes it can be seen autosomal dominant
pattern.
50.
51.
52. REFERENCES
• Genetics for nurses, Kamal Jyoti 1st Ed. 2012
• http://www.rightdiagnosis.com/l/leydig_cells_hypo
plasia_type_i/intro.htm
• https://ghr.nlm.nih.gov
• Cell biology, Genetics, Molecular Biology, Evolution
and Ecology..Dr. P.S. Verma and Dr. V.K. Agarwal
Book. 2008
