1 - Genetics and Teratogens

During ___, daughter chromosomes separate

Mitosis

During ___, homologous pairs separate

Anaphase I

During _____, crossing over occurs

Prophase I

During ___, sister chromatids separate

Anaphase II

Name the pattern of inheritance : Huntington’s Disease

Autosomal dominant

Name the pattern of inheritance : Retinoblastoma

Autosomal dominant

What gene is affected in retinoblastoma?

RB locus on chromosome 13q14

Name the pattern of inheritance : Familial hypercholsterolemia

Autosomal dominant

Name the pattern of inheritance : Wilms tumor

Autosomal dominant

Name the pattern of inheritance : Osteogenesis imperfecta, Marfan’s syndrome and Ehler Danlos

Autosomal dominant

Name the pattern of inheritance : Cystic fibrosis

Autosomal recessive

What gene is affected in cystic fibrosis?

Deletion of 3 bases on chromosome 7

How does CF affect the body?

Causes thick sticky mucus to build up in the lungs and digestive tract.

T/F : CF can lead to fluid in the lungs and potentially respiratory failure

True

Which demographic is most likely to be affected by CF?

Caucasians

Name the pattern of inheritance : Phenylketonuria (PKU)

Autosomal recessive

What is PKU?

A metabolic disorder in which phenylalanine hydroxylase is deficient. Phe cannot be properly metabolized.

Which gene is affected in PKU?

Chromosome 12

What should people with PKU avoid in their diet, as it can cause brain damage?

Aspartame

What does phenylalanine hydroxylase usually metabolize pheynlalanine into?

Tyrosine

Name the pattern of inheritance : Tay Sach’s

Autosomal recessive

Production of what substance is altered in Tay-Sach’s disease?

N-acetylhoxosaminidase

This disease results in the accumulation of unprocessed gangliosides in brain cells

Tay-Sachs disease

This disease is most common among Jewish people and CNS degradation ultimately leads to death

Tay-Sachs disease

Name the pattern of inheritance : Albinism

Autosomal recessive

What enzyme converts tyrosine → DOPA and is affected by albinism?

Tyrosinase

Name the pattern of inheritance : Wilson disease

Autosomal recessive

Name the pattern of inheritance : Oculocutaneous albinism

Autosomal recessive

Name the pattern of inheritance : G6PD deficiency

X-linked recessive

Name the pattern of inheritance : Hemophilia

X-linked recessive

Name the pattern of inheritance : Colorblindness

X-linked recessive

Name the pattern of inheritance : Hypertricosis

Y-linked inheritance

Name the pattern of inheritance : Incontinentia pigmenti

X-linked dominant

Name the pattern of inheritance : Leber’s disease

Mitochondrial inheritance

Name the pattern of inheritance : Diabetes

Mitochondrial inheritance

Disease in which the body does not produce or properly use insulin

Diabetes

Diabetes affects which HLA class?

HLA-DR and HLA-DQ

This disease is caused by defects in the mitochondria’s ETC and leads to optic nerve degeneration and blindness

Leber’s optic neuropathy

Which gene is mutated in Leber’s optic neuropathy?

NADH dehydrogenase subunit 4

Which disease involves an inappropriate substitution of valine where glutamic acid should be?

Sickle cell anemia

More than 2 copies of entire chromosome sets (n>2)

Polyploidy

Abnormal number of chromosomes, addition or loss of one or more chromosomes

Aneuploidy

Monosomy (XO)

Turner syndrome

Trisomy 21

Down’s sydrome

Trisomy 18

Edward’s syndrome

Trisomy 13

Patau’s syndrome

In which trisomy do most babies die before birth?

Patau syndrome

Cyclopia, polydactyly, and rocker-bottom feet are common findings in :

Patau syndrome

Cyclopia, polydactyly, and rocker-bottom feet are common findings in :

Patau syndrome

Most babies die before OR shortly after birth in which trisomy?

Edward’s syndrome

Central apnea (breathing stops), overlapping fingers, low-set ears, and rocker-bottom feet are common findings of :

Edward’s syndrome

Congenital heart disease, slanted eyes, epicanthal folds, brushfield spots, and a large wrinkled tongue are common findings of :

Down syndrome

Webbed neck, coarctation of the aorta, and poor breast/ovary development are common findings of :

Turner syndrome

T/F : Those affected with Turner syndrome will still menstruate

False

Agents that can produce a permenant alteration of structure or function in an organism

Teratogen

_____ depends upon the ability of the agent to cross the placenta

Teratogenicity

The embryo is most susceptible to teratogenic effects during _________

Periods of rapid differentiation

The most common etiology of teratogens is ____ or _____

Unknown or multifactorial

Teratogens are harmless and only become harmful once exposure reaches a certain level

Threshold effect

Risk is greatly magnified when an embryo or fetus is exposed to more than one teratogen

Interaction effect or cumulative risk

What are the 4 main mechanisms of teratogenicity?

• Cell growth

• Cell migration

• Cell and tissue interactions

• Cell death

Teratogen exposure during early gestation is more likely to cause ________

Major structural abnormalities

Teratogen exposure later in gestation will cause ______

Physiological deficits and minor structural abnormalities

Teratogens can affect the _______ at any point throughout gestation

Central nervous system

TORCH : T

Toxoplasma

TORCH : O

Others : syphilis, chickenpox, HIV

TORCH : R

Rubella

TORCH : C

Cytomegalovirus

TORCH : H

Herpes virus

Which drug can cause fetal hydantoin syndrome?

Phenytoin

Which skin medication has an especially high malformation rate of 50%?

Isoretinoin

Which medication causes growth retardation and infant death?

Aspirin

Which drug, if taken in the 3rd trimester, can cause pulmonary hypertension?

Ibuprofen

Which drug can cause renal insufficiency and hypocalvaria?

ACE inhibitors

Which drug, when taken in the 1st trimester, can cause heart defects like Ebstein’s anomaly?

Lithium

Displaced tricuspid valve that allows blood back into the right atrium

Ebstein’s anomaly

Which commonly consumed substance can lead to miscarriage and low birth weight?

Caffeine

This medication was previously prescribed to pregnant women as a nausea medication, and later was shown to cause parts of limbs missing and feet/hands connecting directly to the torso.

Thalidomide

This commonly taken medication, if continued throughout pregnancy can cause heart defects.

Oral contraceptives

This substance compromises the functioning of the placenta

Alcohol

T/F : The woman’s body requires a lot more alcohol to to metabolize alcohol

True

Microcephaly, and malformation of the heart, limbs, joints, and face are all symptoms of

Fetal alcohol syndrome

Hyperactivity, seizures, tremor, and impaired motor function are all symptoms of

Fetal alcohol syndrome

T/F : Mental retardation, slow physical growth and small size are NOT symptoms of fetal alcohol syndrome

False

What facial features are most commonly seen in those with fetal alcohol syndrome?

Epicanthal folds and a smooth philtrium

Nicotine _____ blood vessels which reduces blood flow to the uterus

Vasoconstricts

Nicotine raises concentration of ____ in the mother and fetus’s bloodstream, resulting in low birth weight and CNS impairment

Carbon monoxide (CO)

Cleft lip, abnormal lung functioning, SIDS, miscarriage, low birth weight, and ectopic pregnancy can all result from

Nicotine consumption and cigarette smoking during pregnancy

What are the 3 diagnosis methods used to determine teratogenicity?

Ultrasound, amniocentesis, and chorionic villus sampling