Gene disorders

Question 1

Diseases can be caused in three ways

Answer 1

Environmental, Genetic or both

Question 2

What is a mutation?

Answer 2

A permanent change in Dna

Question 3

Mutations can be divided into three categories

Answer 3

Genome, Chromosomal, Gene mutation

Question 4

What is a Genome Mutation?

Answer 4

a change in the whole chromosome

Question 5

Chromosome mutation

Answer 5

A visible change in the chromosome

Question 6

Gene mutation

Answer 6

may result in a single base error

Question 7

A gene can be altered in three ways. What are they?

Answer 7

Deletion, addition, substitution of a single base

Question 8

what is translation

Answer 8

from mRNA to DNA

Question 9

what are some of the effects on Gene Mutation

Answer 9

Interefere with protein synthesis, Abnormal proteins formed, produce abnormal mRNA, defects carried over into translation ( RNA to Proteiin)

Question 10

HOw many genetic disorders are known currently?

Answer 10

4000

Question 11

are most disorders common or rare?

Answer 11

Rare

Question 12

some gene disorders can be an advantage to the patient. for example

Answer 12

Sickle Cell carriers, immunity to malaria.

Question 13

three types of genetic disease

Answer 13

single gene mutation, including mendelian disorders and non- mendelian disorders, multifactorial and polygenic disorders.

Question 14

Mendelian mode of inherence definition

Answer 14

he manner by which genes and traits are passed from parents to their children. The modes of Mendelian inheritance are autosomal dominant, autosomal recessive, X-linked dominant, and X-linked recessive. Also known as classical or simple genetics.

Question 15

Karyotype

Answer 15

No. and appearance of chromosomes in the nucleus of a human cell.

Question 16

how many chromosmes are in a karytope?

Answer 16

46 or 22 pairs

Question 17

Autosome

Answer 17

any nuclear appearance other than the sex chromosomes

Question 18

X linkage

Answer 18

Genes on the X chromosome

Question 19

what type of karyotype is this?

Answer 19

Male

Question 20

Disorders of Mendelian fashion may be

Question 21

Disorder of mendelian fashion may be

Answer 21

autosomal or Xlinked

Question 22

Autosomal Dominant.

Answer 22

th elocus is on an autosomal chromosome and only one mutant allele is required for expression of the phenotpye.

Question 23

RecessiveThe locus is on an autosomal chromosome and both alles must be mutant alleles to express the phenotype.

Answer 23

The locus is on an autosomal chromosome and both alles must be mutant alleles to express the phenotype.

Question 24

X linked

Answer 24

the locus is on the X chromosome and mutant allele/s is required for expression of the phenotype in females.

Question 25

Disorder of non- mendelian fashion: mitochondrial inheritance

Answer 25

the locus is on the mitochondrial chromosome

Question 26

Autosomal Dominant under single gene mutatution

Answer 26

* Mutated gene is located on autosome * both genders affected * presence of a single mutant is suffiecent to result in a mutant phenotype * affected person are heterozygous * multiple generations affected * affected persons has 50% risk of transmitting disease to any offspring

Question 27

this karytogram shows?

Answer 27

Autosomal Dominant Pedigree

Question 28

Examples of autosomal Dominant disorders

Answer 28

* Familial Hypercholesterolamia ( high cholesterol, Cadiovasicular disease, atherosclerosis). * achondrplasia ( dwarism) * neurofibromatosis * Hungtingtons' disease

Question 29

Autosomal Rescessive

Answer 29

1. muatef gene located on autosome 2. male and female affected\ 3. Ar Traits and disorder only mainfest whe the male allled show no feature of the disorder and are healty cariers 4. The AR disorder must be inherited throug both parents ( carier heterozygotes) 5. offspring allele person who are heterozygotes for the same autosomal recessive allele have 1 in 4 chance of being homozygous for that alled.

Question 30

what is this pedigree showing?

Answer 30

Autosomal recessive

Question 31

Example of Autosome Recessive

Answer 31

Sickel cell anaemia thalassemia Cystic fibrosis phenylketonuria

Question 32

X linked

Answer 32

1. Genrally manifest in males 2. affected fathers have no affect ed son and no normal daughters 3. affected daughter are obligate carriers 4. never transmitted directly from father to son 5. son of the carieer females have a 50% chance of inheriting the disorder 6. both males and females offspring of affected females have a 50% chance of inheriting th edisorder.

Question 33

Examples of X linked

Answer 33

* Haemophilia A - Abnormal bledding * Haemophilia B - abnormal bleeding * Duchenne muscles dystrophy * Fragile syndrome

Question 34

Mitochondrial inheritance

Answer 34

* Maternal inheritance * the father does not contribute * all children of an affected female will inherit the mutated mDNA

Question 35

Mt. Inheritance : Leber's Hereditary optic neuropathy( LHON)

Answer 35

BIlateral loss of central vision doe to optic nerve atrophy in young adults, affected persons matybe male or female

Question 36

Multifactorial Disorder

Answer 36

Recur in families, without showing any characteristic asscoaited with the effects of multiple genes in combination with lifestyle and environment factors include a number of development disorder and many common disorder of adult life e.g.

Question 37

Examples which can be multifactorial

Answer 37

* Cleft lip * Neural tube defect * Congenital heart disease * gout * alzeheimer degeneration * hypertensions

Question 38

Cytogenic Disorders

Answer 38

**Alterations** in the number or structure of chromosomes and may affect autosome or sex chromosomes.

Question 39

Aneuploidy

Answer 39

Changes in the number of individual chromomes in a cells

Question 41

monosomy

Answer 41

an autosomal cell with only 1 copy of a chromosome (lethal abnormality)

Question 42

trisomy

Answer 42

a cell with 3 copies of a chromosome

Question 43

nullisomy

Answer 43

a cell with no copies of chromosomes

Question 44

What are the three well know defined autosomal chromosome trisomy disorders

Answer 44

21, 18, 13

Question 45

What is this disease and its features

Answer 45

Edwards syndrome :Characteristic facial features, mental retardation, overlapping fingers, poor development and growth

Question 46

what is this disease and its hallmark?

Answer 46

Patau Syndrome : sever sleft and lip, polydactyl. mental retardation, poor development

Question 47

Sex chromosome disorders

Answer 47

1. problems related to sexual development and fertility 2. discovered at time puberty 3. trisomic types are the most frequent ( XXY, XYY, XXX) are rare in spontaneous abortion 4. retardation related to the number of X chromosome 5. If you have at least one "Y" chromosome, you are male

Question 48

Klinefelter's Syndrome

Answer 48

1. Hypogonadism 2. #1 cause of male infertility 3. No retardation unless more X 4. tall and thin males with long limbs, atrophic testes, small penis 5. breast

Question 49

Turner's Syndrome

Answer 49

1. failure of puberty 2. neck webbing 3. short stature and broast chest 4. congenitial hear defects

Question 50

true harmaphodrite have

Answer 50

ovaries and testes , often of the same side

Question 51

What is Velocardiofacial syndrome?

Answer 51

Arises doe to deletion of segment of the long arm of chromosome 22.