GENETICS

Question 1

Either a person has two unhealthy genes (is homozygous dominant) or is heterozygous, with the gene causing the disease stronger than the corresponding healthy recessive gene for the same trait

Answer 1

Autosomal Dominant Disorders

Question 2

a progressive neurologic disorder, characterized by loss of motor control and intellectual deterioration

Answer 2

Huntington disease

Question 3

1. Facioscapulohumeral muscular dystrophy
2. osteogenesis imperfecta
3. Marfan syndrome
4. Marfan syndrome

Answer 3

Autosomal Dominant Disorders

Question 4

a disorder that results in muscle weakness

Answer 4

Facioscapulohumeral muscular dystrophy

Question 5

a disorder of connective tissue that results in an individual being thinner and taller than usual and perhaps with associated heart disorders

Answer 5

Marfan syndrome

Question 6

a disorder in which bones are exceedingly brittle

Answer 6

osteogenesis imperfecta

Question 7

This tend to be biochemical or enzymatic. This disease do not occur unless two genes for the disease are present (i.e., a homozygous recessive pattern).

Answer 7

Autosomal Recessive Inheritance

Question 8

1. CF
2. Adrenogenital Syndrome
3. Albinism
4. Tay-Sachs Disease
5. Galactosemia
6. Phenylketonuria
7. Limb-girdle muscular dystrophy
8. Rh factor incompatibility

Answer 8

Autosomal Recessive Inheritance

Question 9

Some genes for disorders are located on, and therefore transmitted
only by, the female sex chromosome (the X chromosome). Their
transmission is termed X-linked inheritance. If the affected gene is
dominant, only one X chromosome with the trait need be present for
symptoms of the disorder to be manifested.

Answer 9

X-Linked Dominant Inheritance

Question 10

a progressive kidney failure disorder.

Answer 10

Alport’s Syndrome (X-linked Dom)

Question 11

The majority of X-linked inherited disorders are not dominant,
but recessive. When the inheritance of a recessive gene
comes from both parents (homozygous recessive) it appears
to be incompatible with lif

Answer 11

X-Linked Recessive Inheritance

Question 12

1. Hemophilia A & Christmas Disease
2. Color Blindness
3. Duchenne
4. Fragile X-syndrome

Answer 12

X-Linked Recessive Inheritance

Question 13

blood-factor deficiency

Answer 13

Hemophilia & Xmas Disease

Question 14

pseudo hypertrophic muscular dystrophy

Answer 14

Duchenne

Question 15

a cognitive challenge syndrome

Answer 15

Fragile X Syndrome

Question 16

Visual presentation of the chromosome patterns
of an individual

Answer 16

Karyotyping

Question 17

Elevated level: spinal cord diseases
Decreased: trisomy 21

Answer 17

Maternal Serum Screening

Question 18

Involves retrieval and analysis of chorionic villi

Answer 18

Chorionic Villi Sampling

Question 19

Reveals genetic abnormalities like
retinoblastoma, myotonic dystrophy (muscle
problems), sickle cell anemia, thalassemia

Answer 19

Chorionic Villi Sampling

Question 20

Withdrawal of amniotic fluid through the
abdominal wall at 14th – 16th week, aspirate 20 ml

Answer 20

Amniocentesis

Question 21

Removal of blood from fetal umbilical cord at
about 17 weeks using amniocentesis technique

Answer 21

Percutaneous Umbilical Blood Sampling

Question 22

• PATAU syndrome
• Extra chromosome 13
• Severely cognitively challenged
• Midline disorders: cleft lip and palate, heart disorders, abnormal genitalia
• Do not survive beyond early childhood

Answer 22

Trisomy 13 Syndrome

Question 23

Trisomy 13 Syndrome Midline disorders:

Answer 23

cleft lip and palate, heart
disorders, abnormal genitalia

Question 24

• EDWARDS syndrome
• Three copies of chromosome 18
• Severely cognitively challenged
• Small for gestational age, low-set ears, small jaw, congenital heart defects, misshapen fingers and toes, rounded soles of the feet
• Do not survive beyond infanc

Answer 24

Trisomy 18 Syndrome

Question 25

* Missing portion of chromosome 5 * Abnormal cry (sound of a cat) * Small head, wide-set eyes, downward slant to the palpebral fissure of the eye, recessed mandible * Severely cognitively challenged

Answer 25

CRI-DU-CHAT Syndrome

Question 26

* GONADAL DYSGENESIS * One functional chromosome * Short in stature * Small and nonfunctional ovaries * Webbed and short neck/wide neck folds * Congenital anomalies – coarctation of the aorta, kidney disorders * Severely cognitive challenged

Answer 26

Turner Syndrome

Question 27

* Males with extra X chromosome * At puberty, secondary sex characteristics do not develop * Testes remain small and produce ineffective sperm * Gynecomastia (increased breast size) * High risk of male breast cancer

Answer 27

Klinefelter Syndrome

Question 28

* Common cause of cognitive challenge in males * X-linked disorder – one long arm of an X-chromosome is defective * Hyperactivity, aggression, autism * Deficits in speech and arithmetic * Large head, long face with a high forehead, prominent lower jaw, large protruding ears, obese * After puberty, enlarged testicles may become evident * Fertile and can reproduce * Carrier females – may show physical and cognitive characteristics

Answer 28

Fragile X Syndrome

Question 29

* Most common chromosomal disorder * High risk – women more 35 years old * Nose id broad and flat * Eyelids have extra fold of tissue at the inner canthus (epicanthal fold)

Answer 29

Down Syndrome (Trisomy 21)

Question 30

* Palpebral fissure (opening between the eyelids) tends to slant laterally upward * Iris of the eye have white specks (Brushfield spots) * Protruding tongue (due to small oral cavity) * Back of the head is flat * Neck is short * Low set ears

Answer 30

Down Syndrome (Trisomy 21)

Question 31

* Poor muscle tone – rag doll appearance * Short and thick fingers * Palm of the hand shows peculiar crease (simian line) – a single horizontal crease * IQ less than 20 * Congenital heart disease * Prone to Upper respiratory Tract Infection (URTI), Acute Lymphocytic Leukemia (ALL) * Life span is 50 -60 years

Answer 31

Down Syndrome (Trisomy 21)