Questions:
Mutations & Genetic Disorders
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IN ____
Mutations
•Any mistake or ______________________ in the DNA
sequence (doesn’t always mean bad)
Point mutation:
•Change in one nitrogen base in DNA
•Ex: albinism
CHROMOSOMAL MUTATIONS
•Changes in chromosome structure
1) INVERSION:
•the order of genes on a chromosome is inverted
2) TRANSLOCATION:
• the movement of a chromosome fragment
to a nonhomologus chromosome
3) DELETION
•Loss of a few bases
•Loss of large regions of a chromosome
4) DUPLICATION
•Duplication of a few bases
•Duplication of large regions of a chromosome
Crossing Over
•Occurs when chromosomes
__________________________.
•2 chromosomes overlap.
•Some genes cross over and switch places
NONDISJUNCTION
•chromosome pair ___________________________________ properly
during meiosis
Monosomy:
•gamete has _____________________ chromosome than it should
•______________ chromosomes is the result
•Ex: Turner syndrome--Missing a sex chromosome
Trisomy:
•Gamete has _____________________ chromosome than it should
•Result is ______ chromosomes
•Ex: Down’s Syndrome--Extra #21 chromosome
Methods of Detection
Chorion villi sampling:
• Take sample of the chorion
(________________________________________)
• Chemical tests and ___________________________
performed
Logan Warren Ultrasound
Questions:
Ultrasound:
•_____________________________ are used to generate an image of the unborn child.
•Used to detect abnormalities of limbs, organs, etc.
Amniocentesis:
• __________________________surrounding the fetus is drawn out by needle
• ___________________________________ are collected and grown in a lab.
• Chromosomes can be then Karyotyped
Autosomal Disorders
Down’s Syndrome(Trisomy 21)/Patau’s Syndrome(Trisomy 13)/Edward’s Syndrome(Trisomy 18)
Down’s Syndrome (DS)
 Excess ____________ chromosome
 Prenatal testing can be done
 Result of chromosomal mutation
 1 in _______________ people born with this
 Likelihood of having a child with DS ________________ with advancing maternal age
 Symptoms: mental retardation, upward slant to eyes, small mouth, abnormal ear shape,
decreased muscle tone
 _________________
Patau’s Syndrome & Edward’s Syndrome
 _________________ abnormalities
 Very severe conditions
 Most affected _________________ during first few weeks of life
Deletion Disorders
Angelman Syndrome/Prader-Willi Syndrome
Angelman Syndrome
 Inappropriate laughter with convulsions
 ________________________________
 Mental retardation
Prader-Willi Syndrome
Extremely floppy
___________________________
Mild mental retardation
Sex Chromosome Disorders
Klinefelter’s Syndrome/Turner’s Syndrome/Fragile X Syndrome
Klinefelter’s Syndrome
 47, ___________
 1 in 1000 ____________ live births
 Mild learning difficulties
 Taller than average with long lower limbs
 Show mild enlargement of breasts
 _______________________ (absence of sperm)
 Treat with testosterone
Turner’s Syndrome
 45, X
 Low incidence
 ________________________
 Ovarian failure
 Normal intelligence
 Short stature
 Estrogen therapy
Questions:
Fragile X Syndrome
 Most common inherited cause of mental retardation
 1 in _______________ males
 High forehead, prominent jaw, autism
 Gap in __________ chromosome
Single Gene Disorders
Cystic Fibrosis/Hemophilia/Sickle Cell Anemia/Phenylketonuria
Cystic Fibrosis (CF)
 _______________________ disorder
 Mutation stops production of protein in lung cells,
pancreas
 Thick _________________, bacterial infections in lung
 “sweat test”
 Most common in _____________________ (1 in 3300)
 Chest percussions, diet supplements
 _______________________ life expectancy
Hemophilia
 ___________________
 Failure of blood to clot
 _______________ in females
 Injections with clotting factors to stop bleeding episodes
 _____________________ a year in treatment
Sickle Cell Anemia
 Mutation in _________________________
 “sickle” shape to RBC
 Screening tests
 Most common in _______________________
 Pain associated with blocked vessels, causes
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Summary:
(1 in 375)
______________________ (fatigue)
 Common where mosquito-borne malaria is present
PKU
Mutation disrupts function of _________________
Leads to high phenylalanine levels in brain (poisons)
Mental retardation, epilepsy
Screening newborns (__________________)
1 in ___________________ Caucasian births
Extremely ____________ in African-Americans
Look normal
Need low-protein diet, smelly formulas