Basic methods of genetic testing. Pedigree analysis. Seminar 1

Question 1

What is Medical Genetics?

Answer 1

any application of
genetics to medical practice, including:
 Studies of the inheritance of diseases in
families
 Mapping of disease genes to specific
locations on chromosomes
 Analyses of the molecular mechanisms
through which genes cause disease
 Diagnosis, treatment and prophylaxis of
genetic disease

Question 2

Approx how many genes per chromosome

Answer 2

900

Question 3

How many genes do humans have approx

Answer 3

20,000

Question 4

How many nucleotide base pairs do humans have

Answer 4

3 billion

Question 5

How are genetic disorders caused?

Answer 5

Due to alterations in genes or combinations of genes, or in chromosomes

Question 6

The 5 groups of genetic disorders

Answer 6

Chromosome
Single-gene
Multifactorial
Mitochondrial
Acquired genetic diseases due to somatic cell mutations

Question 7

Chromosome disorders definition

Answer 7

Entire chromosomes or segments are missing, duplicated or mutated

Question 8

Single-gene disorders def

Answer 8

Single genes are altered

Question 9

Classification of single gene disorders through inheritance?

Answer 9

Autosomal dom
Autosomal recessive
X-linked dom
X-linked recessive

Question 10

Multifactorial disorders

Answer 10

Due to a combination of multiple genetic and environmental causes which lead to a genetic predisposition

Question 11

Examples of multifactorial disorders

Answer 11

Cleft lip
Cleft palate
Heart disease
Diabetes
Neural tube defects

Question 12

Mitochondrial disorders

Answer 12

Disorders caused by alterations in the small cytoplasmic mitochondrial chromosome

Question 13

How many mitochondrial genes are there?

Answer 13

37

Question 14

Examples of chromosome disorders

Answer 14

Downs 
Edwards
Patau
Klinefelter 
Turner syndrome

Question 15

Examples of multifactorial disorders

Answer 15

Congenital malformations
Cleft lip
Clubfoot 
Neural tube defects
Heart disease

Question 16

Examples of single-gene disorders

Answer 16

Marfan syndrome
Osteogenesis imperfecta
Cystic fibrosis
Hungtington disease

Question 17

Examples of Mitochondrial Diseases

Answer 17

Kaerns-Sayre syndrome
• Leber hereditary optic neuropathy
(LHON)
• Mitochondrial encephalopathy, lactic
acidosis, and stroke-like episodes
(MELAS)

Question 18

Basic methods in genetic testing

Answer 18

Pedigree method 
Cytogenetics
Molecular – cytogenetics
Molecular genetic methods (DNA
analysis)

Question 19

Pedigree analysis

Definition

Answer 19

the drawing of the pedigree chart which is the

first stage of genetic counselling.

Question 20

Uses of pedigree analysis

Answer 20

Analyses patterns of inheritance,
genotypes of family members
Establishes genetic diagnosis
Can calculate risk

Question 21

Proband

Answer 21

the index case through whom a
family is identified. This is the starting point
for the genetic study

Question 22

Consultand

Answer 22

An individual who presents for

genetic counseling

Question 23

Consanguinity def

Answer 23

when people have a

common ancestor

Question 24

what does Consanguinity increase?

Answer 24

the frequency of genetic disease and mortality and is often seen in autosomal recessive diseases