Genetics & Inherited Disorders

What is nondisjunction?

Failure of homologous chromosomes to separate properly during meiosis/mitosis, leads to chromosomal disorders like Down Syndrome

What environmental agents can mutations arise in?

Radiation, chemicals, viruses

What does a gene with complete penetrance mean?

All individuals with the gene will expression the associated condition -- no exceptions

What does it mean if a female is a carrier of fragile X syndrome?

She is heterozygous and may pass the gene to her children, especially if homozygosity occurs.

The first _____ months of pregnancy are the most sensitive time for fetal development and teratogenic exposure

two

Can parents be healthy and still have a child with cystic fibrosis?

Yes if both are carriers of the recessive CF gene

What are traits of adolescent males with Klinefelter syndrome?

Gynecomastia, sparse facial/pubic hair, and tall stature

What traits are associated with an infant with trisomy 21 (Down Syndrome)

IQ of 25-70, flat nasal bridge, protruding tongue, low-set ears

What are teratogenic agents?

Alcohol, drugs, infections, things that cause the most harm if exposure occurs during early pregnancy

Which type of genetic disorder typically shows more consistent symptoms: autosomal dominant or autosomal recessive?

Autosomal recessive disorders

If a male has fragile X syndrome, who inherits the gene?

All daughters will be carriers, but sons will not inherit.

What is the consequence of a multifactorial disorder with one child?

Increased risk of recurrence in future children?

What higher risk do patients with Down syndrome have?

Higher risk for congenital heart defects

What is the risk of another son being affected by hemophilia A in a family with one affected son?

There is a 50% chance that another son could also be affected.

What is the significance of telomeres? How do they worsen? What can occur if there are no telomeres?

Controls cell division, shortens with age (like the plastic cap of a shoelace, overtime they wear out); cancer

How many chromosomes/pairs of chromosomes are they? How many pairs control autosomes, and which pair controls sex?

46 chromosomes/23 pairs, 22 control autosome, 23rd controls sex

What is the difference between genotype and phenotype?

Genotype describes what a person has/ the genetic makeup, while phenotype describes a person's physical/observable characteristics

What type of disease is Huntington's disease?

Autosomal dominant

What is hemophilia? What type of disease is it?

Condition where one has trouble clotting, leading to easy bruising and nonstop bleeding; X-linked recessive

What are some symptoms of Turner Syndrome

absense of ovaries, short stature, webbing of neck, edema, under-developed breasts, wide nipples