2.1 MedInt, PLTW

made for unit 2.1 of Project Lead the Way's Medical Intervention curriculum

Cell-Free fetal scanning

• Non-invasive prenatal testing (NIPT)

• Looks for some common forms of abnormal chromosomes in small fetal DNA in your blood

• Cannot be performed before 10 weeks, as the fetal DNA is too small.

Serum Screening

• Tests various protein levels to determine the risk for abnormal chromosome numbers.

• Multiple types performed at different times during pregnancy

• Cannot be performed until 11 weeks

What does Physical abnormality screening test for?

Missing or extra chromosomes that can cause physical abnormalities

Nuchal Translucency

• Uses ultrasound to measure the thickness of the back of the baby’s neck

• Gives clues for risks about abnormal chromosomes as well as possible physical abnormalities like heart defects

• 11 to 14 weeks

Quad Screening

• Measures levels of four substances in your blood 

• Determines risk of chromosomal abnormalities

• 15 to 22 weeks

What does Quad Screening test?

Four substances found in the mother’s blood

What does Nuchal Translucency test for?

The thickness of the child’s neck

What does Cell-Free fetal scanning test for?

common forms of abnormal chromosomes in the blood

When can Cell-Free fetal scanning be performed?

after 10 weeks

When can Serum Screening be performed?

After 11 weeks

When can Nuchal Translucency be performed?

11-14 weeks

What is prenatal genetic testing?

A form of genetic testing performed before or during pregnancy that gives parents information about possible birth defects or genetic abnormalities.

What is down’s syndrome?

A chromosomal disorder that results in physical defects and developmental problems. Someone with Down’s syndrome can live a normal life with proper care.

What causes Down’s syndrome?

A mutation called Trisomy 21, which causes chromosome 21 to have three copies instead of the normal two.

What is a Karyotype?

An organized set of a person’s chromosomes.

Single Gene

A type of genetic disorder that affects one gene sequence, resulting in a different protein. Includes homozygous dominant, homozygous recessive, & heterozygous, as well as sex-linked disorders that happen on the x or y chromosomes.

Multifactorial

A type of genetic disorder caused by a combination of environmental factors &/or mutations in multiple genes.

Chromosomal

A type of genetic disorder caused by missing or added on genes. Can also result in missing or added on chromosomes.

Mitochondrial

A type of genetic disorder affecting the organelles in cells that convert energy. Extremely rare, and can only be passed down from mother to daughter.

TAS2R38

The gene we are testing for in our 2.1.3 lab. It is responsible for being able to taste phenylthiocarbamide.

Denaturation

The first step of the PCR process. Heat breaks apart DNA strands.

Annealing

The second step of the PCR process. The heat is lowered, and DNA primer binds to their starting positions.

Extension

The third step of the PCR process. Temperature is raised to the proper environment for the select DNA polymerase enzyme, which synthesizes the new DNA strand from the 5’ to 3’ direction.

Restriction enzyme

An enzyme that cuts DNA into very specific fragments.

What restriction enzyme are we using in the 2.1.3 lab?

HaeIII

What gene does HaeIII splice?

GG|CC

CC|GG

How many gene fragments are in a dominant allele of TAS2R38? (in relation to heterozygous sequence)

2

How many times does a homozygous sequence repeat?

2

How many fragments are in a recessive allele of TAS2R38? (in relation to heterozygous sequence)

1

How many gene fragments are in a homozygous dominant sequence of TAS2R38?

4

How many gene fragments are in a homozygous recessive sequence of TAS2R38?

1

Gel electrophoresis

A lab technique separating DNA, RNA, or proteins by size, with smaller fragments moving faster and reaching further.

Amniocentesis

A prenatal test used to determine fetal abnormalities, using a needle that travels through the abdomen to gather amniotic fluid.

Chronic villus samplimg

A prenatal test used to determine fetal abnormalities by taking a sample of cells from the placenta.