Genetic and chromosomal disorders in children

Question 1

It occurs when a mutation (a harmful change to a gene, also known as a pathogenic variant) affects your genes or when you have the wrong amount of genetic material.

Answer 1

Genetic Disorders

Question 2

The basic physical and functional unit of heredity.

Answer 2

Gene

Question 3

This is made of DNA (deoxyribonucleic acid), which contains instructions for cell functioning and the characteristics that make you unique.

Answer 3

Genes

Question 4

It is the molecule that carries genetic information for the development and functioning of an organism

Answer 4

DNA

Question 5

DNA is made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as

Answer 5

Double Helix

Question 6

They are a pair of genes in homologous chromosomes present at a specific locus (specific physical location of a gene or other DNA sequence on a chromosome, like a genetic street address).

Answer 6

Alleles

Question 7

Condition where the paired genes are similar on homologous chromosomes for a character.

Answer 7

Homozygous

Question 8

Condition where the paired genes are not similar on homologous chromosomes for a character.

Answer 8

Heterozygous

Question 9

A hybrid organism is one that is heterozygous, which means that is carries two different alleles at a particular genetic position, or locus.

Answer 9

Hybrid

Question 10

It is a gene which expresses itself in the presence of a contrasting gene.

Answer 10

Dominant Gene

Question 11

It is a gene which fails to express itself in
the presence of a dominant gene.

Answer 11

Recessive Gene

Question 12

It is a term used to denote the transmission of characters from parents to off springs?

Answer 12

Inheritance

Question 13

The manner in which genes and traits are passed from parents to their children. Disorders are caused by a defect in a single gene that follows the patterns of inheritance by Mendel (1965).

Answer 13

Mendelian Inheritance

Question 14

If a trait or disease manifests itself when the affected person carries only one copy of the gene responsible, along with one normal allele, the mode of inheritance of the trait is called

Answer 14

Dominant

Question 15

If two copies of the defective gene are required for expression of the trait, the mode of inheritance is called

Answer 15

Recessive

Question 16

Disease can be inherited from one parent also.
Can affect both males and females
Can be traced through many generations of a family.
Affected people are heterozygous for the abnormal allele and transmit the gene for the disease to half their offspring, whether male or female.

Answer 16

Autosomal Dominant

Question 17

• Disease can appear only if both parents transmit it.
• Unaffected parents can transmit the trait to their offsprings(if both parents carry recessive gene)
• Siblings may be affected but parents usually are apparently normal
• Abnormal gene remains suppressed and does not manifest in a heterozygous individual.
  The affected person is homozygous for the trait.

Answer 17

Autosomal Recessive

Question 18

The gene is located on the X chromosome, but the gene acts in a dominant manner.
This means that both males and females can display the trait or disorder, by only having one copy of the gene.

Answer 18

X-Linked Dominant

Question 19

This are expressed in females only if there are two copies of recessive gene (one on each X chromosome).

Answer 19

X-linked recessive genes

Question 20

Refers to inheritance of a phenotypic characteristic (trait) that is attributable to two or more genes and their interaction with the environment.

Answer 20

Polygenic inheritance/multifactorial inheritance/ quantitative inheritance

Question 21

Abnormal changes in the number and structure of chromosomes.

Answer 21

Chromosomal mutations

Question 22

Numerical changes are known as

Answer 22

Ploidy Changes

Question 23

Ploidy changes bring about abnormal alterations in the karyotype which causes serious _________.

Answer 23

Genetic Disorders

Question 24

Extrachromosomal sets

Answer 24

Polyploidy

Question 25

An extra or missing chromosome

Answer 25

Aneuploidy

Question 26

One chromosome absent

Answer 26

Monosomy

Question 27

One chromosome extra

Answer 27

Trisomy

Question 28

Part of a chromosome missing

Answer 28

Deletion

Question 29

Part of a chromosome present twice

Answer 29

Duplication

Question 30

Two chromosomes join long arms or exchange parts

Answer 30

Translocation

Question 31

Segment of chromosome reversed

Answer 31

Inversion

Question 32

A chromosome with identical arms

Answer 32

Isochromosome

Question 33

A chromosome forms a ring due to telomere deletions, which cause ends to adhere.

Answer 33

Ring Chromosome

Question 34

Condition in sex chromosome aneuploids in female

Answer 34

Turner Syndrome

Question 35

Who and when was it first reported Turner Syndrome?

Answer 35

Henry Turner in 1938

Question 36

Turner Syndrome is also called the _____

Answer 36

Ovarian Dysgenesis

Question 37

Abnormal female(sterile) condition

Answer 37

44A+X0

Question 38

Caused by sex chromosomal monosomy, absence of an X chromosome(XO Syndrome)

Answer 38

Turner Syndrome

Question 39

Turner's Syndrome affects ___________ female births.

Answer 39

1 in 2,500

Question 40

Clinical Manifestations of Turner's Syndrome

Answer 40

Short Stature Webbing of Neck Low Posterior Hairline Broad Chest and widely spaced nipples Contraction of the aorta Cubitus Valgus Pigmented Nevi Streak Ovaries, Infertile, Amenorrhea Peripheral Lymphedema at birth

Question 41

Cause of Turner's Syndrome

Answer 41

Lack of Barr Body Missing only part of an X chromosome

Question 42

At birth: (looks normal) Clinical Manifestations

Answer 42

Puffy hands Impaired Lymphflow in feet

Question 43

At sexual maturity: Clinical Manifestations

Answer 43

sparse body hair develops rudimentary / immature ovaries very small uterus, normal cervix and vagina intelligence is normal turner neurocognitive phenotype may cause memory deficits

Question 44

What can be done if a person has Turner's Syndrome?

Answer 44

Hormones (Progesterone and Estrogen)

Question 45

Sex Chromosome Aneuploids: Male

Answer 45

Klinefelter's Syndrome

Question 46

Klinefelter's Syndrome due to an extra X chromosome (47, XXY) caused by

Answer 46

Chromosomal Trisomy

Question 47

What causes Klinefelter's Syndrome?

Answer 47

Extra X chromosome (47, XXY) chromosomal trisomy

Question 48

Klinefelter's Syndrome is first reported by and on?

Answer 48

Klinefelter in 1942

Question 49

Klinefelter's Syndrome is observed in about ____________.

Answer 49

1 in 500 males

Question 50

Clinical Manifestations of Klinefelter's Syndrome

Answer 50

Frontal baldness absent Poor Bread Growth Tendency to grow fever Chest Hairs Narrow Shoulders Breast Development Female-type pubic hair pattern Wipe hips Small testicular size long arms and legs

Question 51

Symptoms of Klinefelter's Syndrome

Answer 51

Immature testes and prostate glands Sparse (thin and dispersed) pubic and facial hair They have very long arms and legs, large hands and feet may develop breast tissue( gynaecomastia) genetic or chromosomal cause of male infertility. Mental retardation in cases of more than 2 X chromosomes. may be slow to learn

Question 52

What can be done if a person has Klinefelter's Syndrome?

Answer 52

Testosterone injections during adolescence can limit limb lengthening and stimulate development of secondary sexual characteristics. Men with XXY syndrome have fathered children, with medical assistance. Doctors select sperm that contain only one sex chromosome and use the sperm to fertilize oocytes.

Question 53

A harmful change to a gene, also known as a pathogenic variant

Answer 53

Mutation