Cystic fibrosis: Evidence for a genetic compound from a family study in cell culture.

Although the majority of patients with cystic fibrosis (CF) show a typical 
clinical course, a minority with the same clinical phenotype at the 
time of initial diagnosis have an atypical (mild) course. Skin fibroblast 
cultures were established from 49 members of the family of one 
such atypical CF adult patient, previously identified (Danes et al. 1976) 
as CF Class II (ametachromatic and no metabolic cooperation with CF 
Class I fibroblasts), the offspring of Class I (metachromatic, metabolic cooperation 
with normal fibroblasts)/Class II mating. The culture phenotype for Class I 
was traced on the maternal side and for Class II on 
the paternal side through consecutive generations and the culture phenotype of 
each class segregated. This family study added experimental evidence to support 
the hypothesis that the atypical (mild) clinical features and course of 
this adult CF patient were due to two different CF genes 
combining to produce a genetic compound expressing a mild form of 
CF. 