Table 1 Phenotypes of the 201 families included.
From: Phenotypic and genetic heterogeneity in a genome-wide linkage study of asthma families
Phenotype | Definition | No. of families |
|---|---|---|
Early onset asthma | occurrence of asthmatic symptoms for one child before the age of 2 years and for his or her sib pair at least before the age of 4 years | 67 |
Extrinsic asthma | all asthmatic children are positive for at least one SPT or specific IgE | 134 |
HDM SPT positive | at least 3 family members with a positive skin prick test (SPT) for HDM | 33 |
HDM RAST positive | at least 3 family members with a positive result of serum specific IgE for HDM | 42 |
Severe asthma | asthma severity index (see table 3) for one asthmatic child is 4 or 5 and for his or her sib pair 3, 4 or 5 | 56 |
Seasonal variation: "Winter-Type" | one affected child suffers from asthma attacks in the winter half-year and his or her sib pair at least not solely in the summer half-year | 39 |
Seasonal variation: "Summer-Type" | one affected child suffers from asthma attacks in the winter half-year and his or her sib pair at least not solely in the summer half-year | 35 |
German nationality | both parents are of German descent | 170 |