16- Sex-linked and Non Traditional Inheritance

Question 1

3 specific rules of inactivation

Answer 1

Random (can be either X)
Fixed (All descendents of a cell have same X inactive)
Incomplete (85% not active)

Question 2

X maintains its own inactivation in three ways

Answer 2

1. Kind of coats itself with RNA, walls itself off
2. Methylation of genes is high (tunring off promoters)
3. Histone Deacetylation= tight dense Barr body

Question 3

Female inheritance of X linked recessive is similar to _____ in regards that______

Answer 3

Autosomal recessive, need two bad copies to be affected

Question 4

X-linked recessive heterozygotes will express the mutation in _____ and their normal cells will_______

Answer 4

50% of cells, compensate

Question 5

X linked recessive, affected father, normal mother

Answer 5

100% daughter carriers, and 100% sons normal

Question 6

Hemophilia A is a defect in ____ on chromosome ______

Answer 6

Factor VIII, X

Question 7

therapy for hemophilia

Answer 7

Factor VIII infusions

Question 8

what % activity of Factor VII to be considered affected by asymptomatic , what mutation is common for this

Answer 8

25%, missense

Question 9

what is the reason for the occurrence of hemophilia

Answer 9

Large Gene- takes more hits

Question 10

early diagnostic indicator of Duchenne Muscular Dystrophy

Answer 10

Creatine Kinase 20x normal limit, pseudohypertrophy of calves

Question 11

milder form of DMD with mildly altered dystrophin and very slow progression

Answer 11

Becker Muscular Dystrophy

Question 12

Normal vision is considered _______

Answer 12

trichromatic

Question 13

Not seeing one of the colors is_____

Answer 13

dichromatic

Question 14

Red-green color blindess is ______inherited

Answer 14

X-linked

Question 15

Reason for red-green color blindness

Answer 15

unequal crossing over of red and green opsins which are adjacent on the X chromosome

Question 16

Females twice as likely to be affected as males in _____

Answer 16

X linked Dominant Inheritance

Question 17

Kidneys can’t reabsorb phosphate

Abnormal ossification, bones bend and distort

Answer 17

Hypophosphatemic rickets

Question 18

Abnormal skin pigmentation and teeth
Neurological and ocular abnormalities
Males lost in utero

Answer 18

Incontinentia pigmenti

Question 19

Autism, ataxia, mental retardation

Some males survive to term

Answer 19

Rett syndrome

Question 20

Difference between LHON and MERRF

Answer 20

MERRF is heteroplasmic meaning people with severe and mild forms within the same family

Question 21

Sherman Paradox

Answer 21

Sisters of NTM are less likely to be affected than are granddaughters of NTM

Question 22

Fragile X expands only in ____, meaning that

Answer 22

female meiosis, offspring of transmitting male have same number as father

Question 23

Fragile X:

Normal copy #, abnormal, NTM

Answer 23

6 to 50, >230, 50 to 230

Question 24

Name 3 XLD diseases

Answer 24

Hypophosphatemic Rickets
Incontinentia Pigmenti
Rett Syndrome

Question 25

Name 3 XLR diseases

Answer 25

Hemophilia A
Duchenne Musclular Dystrophy
Red-Green Color Blindess

Question 26

what gene locus codes for inactive XRNA

Answer 26

XIST

Question 27

defective gene for dystrophin protien, which binds ____ and ____

Answer 27

DMD, F actin, dystroglycan

Question 28

In fragile X syndrome ____ repeats in the ____ gene at the ______

Answer 28

CCG, FMR1, 5’ UTR region

Question 29

2 reasons for mtDNA mutation rate

Answer 29

Oxidation and lack of a repair system

Question 30

Maternal imprinting, paternal deletion

Answer 30

Prader-willi

Question 31

Paternal imprinting, maternal deletion

Answer 31

Angelman’s

Question 32

Single base change in mitochondiral tRNA, heteroplasmic

Answer 32

MERRF or MELAS