Genetic Disorders Flashcards
what is a genetic disorder?
- a disease caused by genetic mutation that is either inherited or arises spontaneously
- a disorder in gene or chromosome structure
-how many pairs of chromosomes do people normally have?
23 (means 46 chromosomes in total)
what is meant by a dominant gene disorder?
- o Refers to a characteristic that is apparent when the relevant gene is present in only one copy. A dominant disorder can be inherited from only one parent
- if one parent is affected and one not, have a 50% chance of inheriting
what is meant by a recessive gene disorder?
- for a recessive allele to produce a recessive phenotype, the individual must have two copies, one from each parent
- Both parents carry a single defective gene (d) but are protected by the presence of a normal gene (N), which is generally sufficient for normal function. Two defective copies of the gene are required to produce a disorder. Each child has a 50 percent chance of being a carrier like both parents and a 25 percent risk of inheriting the disorder.
- 1/4 chance of getting
what are genes?
the basic units of heredity that determine both the physical and mental characteristics of people
-composed of segments of DNA
are male or female children at risk of X-linked disorders?
- males
- carried by mother, male has 50% chance of inheriting
- women are protected by their other x chromosome, but men lack this
- however, women have a 50% chance of being a carrier
what are the two general types of chromosome abnormalities?
numerical
structural
what is meant by a numerical chromosome abnormality?
-an entire single chromosome is either missing or added
what is meant by a structural chromosome abnormality?
-part of chromosome is missing or added, rearranged, adhered to another, or has a fragility on a site
what are some examples of numerical chromosome abnormalities?
- trisomy - an extra copy of one chromosome
- monosomy - missing one chromosome
what monosomy is compatible with life?
turner’s syndrome
-it is the most common sex chromosome abnormality in females, they have a single x chromosome
what is karyotype?
pictorial analysis of chromosomes obtained from treated and stained peripheral blood lymphocytes
what is kleinfelter syndrome?
- a syndrome where males have an extra x chromosome
- have delayed language development, issues with auditory processing, and emotional problems
what kind of chromosomal abnormality is downs syndrome?
a trisomy
each cell has three copies of chromosome 21
what are some effects of trisomy 13?
- mental retardation
- hypotonia
- CHD