David Duffy
Queensland Institute of Medical Research |
Therefore:
Twin A | Twin B | Sibling | ||
---|---|---|---|---|
7 Type of delivery | ||||
a Cephalic (normal headfirst) | 44% | 28% | 65% | |
b Forceps | 21% | 17% | 20% | |
c Caesarian Section | 28% | 30% | 13% | |
d Breech | 8% | 25% | 2% | |
8 Complications | ||||
a Placental Difficulty | 16% | 24% | 11% | |
b Umbilical cord complications | ||||
c Breathing problems (asphyxia) | ||||
d Anaemia | ||||
10 Birth Weight (in gms) | [Median] | 2600 | 2553 | 3405 |
Twin A | Twin B | Sibling | ||
---|---|---|---|---|
1. Has he/she ever suffered from wheezy breathing? (Wheezing is a whistling noise coming from the chest, though it can be heard in the mouth) | 34.0% | 35.3% | 28.3% | |
2. In the last 12 months, how often has he/she had an episode of wheezing | ||||
any | 24% | 24% | 19% | |
more than 12 times | 4.7% | 4.0% | 4.1% | |
5. Does he/she suffer from rhinitis? (Rhinitis is a runny, itchy nose, often with watery and itchy eyes whe he/she DOES NOT have a cold | 12.4% | 14.0% | 14.1% | |
7. Has a doctor ever diagnosed him/her as suffering from: | ||||
asthma | 26% | 26% | 21% | |
allergic rhinitis | 5.4% | 6.4% | 6.8% |
More wheezing, perhaps of a milder nature, but no increase in hayfever.
MZ | DZ | |||
---|---|---|---|---|
Twin A | Twin B | Twin A | Twin B | |
Wheeze | 36.4% | 36.3% | 31.8% | 35.1% |
Asthma | 28.2% | 27.1% | 24.6% | 24.7% |
The probandwise concordance is the estimated recurrence risk:
Group | No. Pairs | Concordance | Risk Ratio |
---|---|---|---|
MZ Female | 512 | 80.0% | 2.4 |
MZ Male | 473 | 83.3% | 2.1 |
DZ Female | 288 | 52.1% | 1.8 |
DZ Male | 323 | 57.5% | 1.5 |
DZ Female-Male | 509 | 40.5% | 1.5 |
DZ Male-Female | 53.1% | 1.5 | |
Sib Male-Male | 375 | 53.2% | 1.6 |
Sib Female-Female | 333 | 52.7% | 2.1 |
The cross-trait correlations can also be analysed to estimate the genetic and environmental correlations. Here is data from a study of 419 adult twins:
DZ correlations upper triangle | |||||
IgE1 | Dp1 | IgE2 | Dp2 | ||
---|---|---|---|---|---|
Twin 1 | logIgE | -- | 0.59 | 0.23 | 0.14 |
Dpter | 0.60 | -- | 0.21 | 0.24 | |
Twin 2 | logIgE | 0.66 | 0.38 | -- | 0.68 |
Dpter | 0.48 | 0.58 | 0.55 | -- | |
MZ correlations lower triangle |
The total sIGE - D. pter wheal size correlations are roughly:
Within-individual | 0.6 |
Within-MZ pair | 0.4 |
Within-DZ pair | 0.2 |
Questionnaire data from 3808 adult Australian twin pairs.
Proportion of variation (×100) due to common and trait-specific genetic and unshared environmental risk factors from a biometrical factor model.
Common | Specific | ||||
---|---|---|---|---|---|
Trait | A | C | E | A | E |
Wheezing | 34 | 06 | 21 | 17 | 23 |
Hayfever | 27 | 28 | 23 | 03 | 19 |
Dust Allergy | 34 | 24 | 41 | -- | 02 |
Eczema | 41 | 10 | 12 | 00 | 36 |
Trait | Common | Specific | ||||
---|---|---|---|---|---|---|
A | D | E | A | D | E | |
Wheezing | 08 | 29 | 09 | 16 | 16 | 24 |
Hayfever | 18 | 23 | 27 | 00 | 21 | 12 |
Dust Allergy | 16 | 38 | 28 | -- | -- | 18 |
Sinusitis | 30 | 0 | 19 | 07 | 02 | 41 |
Bronchitis | 13 | 0 | 07 | 06 | 00 | 42 |
Asthma or wheeze 1980 | BHR+ | BHR- | Not tested | Percent tested |
---|---|---|---|---|
No information | 15 (38.5%) | 24 | 900 | 4.0 |
No symptoms | 88 (31.9%) | 188 | 5393 | 4.8 |
Only as a child | 35 (53.0%) | 31 | 226 | 22.6 |
Occasionally | 57 (59.4%) | 39 | 350 | 21.5 |
Frequently | 70 (92.1%) | 6 | 194 | 28.1 |
Dust Allergy 1980 | SPT+ | SPT- | Percent tested |
---|---|---|---|
Proband (wheeze in 1980 or 1988) | |||
No information | 13 (56.5) | 10 | 19.9 |
No symptoms | 76 (52.0) | 70 | 21.9 |
Only as a child | 13 (86.7) | 2 | 31.9 |
Occasionally | 45 (81.2) | 10 | 24.2 |
Frequently | 96 (82.1) | 21 | 27.2 |
Nonproband (denied wheeze 1980/1988) | |||
No information | 7 (38.9) | 11 | 3.6 |
No symptoms | 55 (37.9) | 90 | 3.2 |
Only as a child | 2 (66.7) | 1 | 7.3 |
Occasionally | 15 (78.9) | 4 | 4.9 |
Frequently | 9 (64.3) | 5 | 4.1 |