Heritibility and genes

Question 1

Heritibility

Answer 1

ASD 90
BPAD > 80
Schizophrenia 80
ADHD 70-80%
Alcohol dependence 60
Major depression 40
Panic disorder 40
Phobia 35
Generalised anxiety 30

Question 2

Schizophrenia

Answer 2

MZ concordance = 41-65%
DZ concordance = 0-28%

One parent:
Child has 13% risk

Both parents:
Child has 46%

Half sibling 4%

Question 3

Schizophrenia genes

Answer 3

Genes include NRG1(8p12), DTNBP1 (6p22), G82 (13q), DAAO (12q), RGS4 (1q21), COMT (22q11), DISC1 (1q42)

Question 4

BPAD

Answer 4

Unrelated member of general population = 0.5-1.5% (5-10% for unipolar depression)

1st degree relative = 5-10% (10-20% for unipolar depression

MZ twin = 40-70% (15-25% for unipolar depression)

Question 5

Genes in BPAD

Answer 5

BDNF

DAO G72/G30

COMT

Question 6

Unipolar depression

Answer 6

1st degree = 5-30%

MZ = 40%

DZ = 11%

Question 7

Shared genes (BPAD and schizophrenia)

Answer 7

DAO & BDNF - more in mood disorders
DISC 1 & NRG - schizophrenia and schizoaffective
Dysbindin - more in schizophrenia
CREB1 (chr2) - unipolar depression

Question 8

AD

Answer 8

1st degree = 15-19%

MZ = 84%
DZ = 40%

Question 9

Familial AD

Answer 9

Amyloid precursor protein (chr21), presenilin 1 (ch 14) and 2 (chr 1) may be responsible for as much as 50% of familial (autosomal dominant) beginning before aged 60

Question 10

AD gened

Answer 10

APOE - genetic factor with highest attributable risk (19q)

APP (Chr 21) - Down’s

Question 11

CADASIL

Answer 11

Notch 3 (19p13.1)

Question 12

FTD

Answer 12

MAPT (17q) (tau)

PGRN (17q) (progranulin)

Question 13

PD

Answer 13

PARK1, PARK4 (alpha synuclein) - 4q 21

PARK2 (parkin gene) - 6q25

PARK 8 (LRRK2 gene) - 12 cen

PARK 6 (PINK1)

Question 14

ASD

Answer 14

MZ = 60%
DZ = 0-10%

Rate in sibling = 2-8%
Rate in sibling of 2 autistic children = 25-30%

Question 15

ADHD

Answer 15

1st degree = 15-60%
2nd degree = 3-9%

Question 16

Panic disorder + social phobias

Answer 16

Early onset panic disorder confers increased risk than later onset disease

10-fold risk in generalized social phobia, 3-4 times in specific phobias

Question 17

Alcoholism

Answer 17

3-4 times higher (adoption studies)

Families may be 4-6

GABRA2 (4p), ADH4, DRD2

Question 18

OCD

Answer 18

Early onset suggests higher genetic risk, increased severity and chronicity increase risk

? more in fathers

MZ = 53-87%
DZ = 22-47%
Before 18 = 10-35%
After 18 = no to 10%