Developmental and Genetic Diseases Flashcards Preview

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Flashcards in Developmental and Genetic Diseases Deck (11):
1

Types of mutations (3)

Genome: + or - of new chrom (dont see a lot cause they die)

Chromosomal: Alteration of 1 or more chroms

Gene: partial or complete
- Partial: one nucleotide base
- Complete: deletion of gene

2

Point mutation (3)

Change in single nucleotide base w/in a gene

- Silent mutation: Mutation codes for same AA

- Missense: Mutation codes for diff AA
Ex: Sickle cell disease (altered shape, dec laminar flow)

- Nonsense: Mutation codes for premature termination of PRO synthesis
Ex: B-thalassemia major

3

Frameshift mutation

insertion/deletion of nucleotides

Ex: Tay-Sachs Disease

4

Tay-Sachs Disease
- Chromosomal disorder?
- CSS
- Tx

Frameshift mutation on chrom 15. Body lacks hexosaminidase A (breaks down gangliosides)

- Chrom disorder: Autosomal recessive
- CSS: Cherry red-spot in eye, deafness, dementia, dec motor tone
- Tx: none, they die

5

Major classes of DNA mutations (3)

- Point mutations
- Frameshift
- Trinucleotide repeat disorders

6

Chromosomal disorders

Trisomy 21
Patau syndrome (trisomy 13)
Turner's Syndrome
Klinefelter syndrome

7

Genetic Disorders (Mendelian patterns of inheritance)

Marfan Syndrome
Familial Hypercholesterolemia
Retinoblastoma
Phenylketonuria (PKU)
Fragile X Syndrome

8

Trisomy 21
- Genetic?
Causes (3)
CSS
How is it detected?
Frequency (2):

Genetic: No, mostly meisosis nondisjunction
Causes:
95% = maternal meiotic nondisjunction
4 = Robertsonian translocation (fusion of both long arms)
1 = mosaicism

CSS: Epicanthic folds, macroglossia, flat face, hematological abnormailities, cardiac malformations, simian crease, M fertile, F not fertile

Dectection: amniocentesis (B-hCG and dec a-fetoprotien)

Frequency:
1:1550 live births < 20 years
1:25 live births > 45 years

9

Patau syndrome (trisomy 13)
- Genetic?
Cause?
CSS:
Frequency
Mean survival

Not genetic
Cause: nondisjunction during maternal meiosis I

CSS: congenital heart defects, cleft lip and palate, deafness, eye/nose defects, mental retardation

Frequency: 1:12,000

Mean survival: 2.5 days

10

Turner's Syndrome
- Genetic?
- Cause (2)
- SHOX gene? And importance?
- CSS

Happens to females. Either X chrom is absent or X chrom is abnormal
No, chromosomal

- Cause: 60% nondisjunction
40% mitotic

- SHOX: transcription protienn, essential for development of skeletal system. *SHOX mutation can happen to males

- CSS: short (<5 ft), infertile, webbed neck, norm intelligence, and wide nips

11

Klinefelter Syndrome
- Genetic?
- Cause (2)
- Incidence?
- CSS

Extra X chromosome (dec testosterone, dec inhibin)
Not genetic

- Cause: 82% karyotype (XXY)
nondisjunction

- Incidence: 1:500 live births

- CSS: Infertile, small balls, gynecomastia (develop boobs), dec face and body hair, tall, learning disabilities (speech and language), inc risk of breast cancer and Lupus