ABSTRACT
To investigate possible modes of inheritance that would explain familial aggregation
in obstructive sleep apnea (OSA), familial correlation and segregation analyses were
performed on data derived from 584 pedigrees with 2019 cases enrolled in the Tucson
Epidemiologic Study of Obstructive Airways Disease (TESOAD) who were at least 10 years
of age and who had information pertaining to snoring and daytime sleepiness. Data
were obtained from the 9th (May 1984 to October 1985) and 12th (February 1990 to October
1992) surveys of the TESOAD, which is a random, stratified sample of the non-Hispanic
Caucasian population of Tucson, Arizona. A snoring phenotype was considered present
if it occurred on at least some nights. A ``sleep apnea'' phenotype was constructed
if participants snored and experienced daytime sleepiness. Familial correlations for
snoring showed significant mother-child and sibling correlations but not father-child
correlations. For sleep apnea, significant parent-daughter but not parent-son or sibling
correlations were observed. Segregation analyses for snoring with regressive familial
effects and sibling, age, and obesity covariates showed no evidence for mendelian
transmission. However, additional familial effects were present that suggested phenotype
aggregation from polygenic or environmental factors, or both. For the sleep apnea
phenotype, similar segregation analyses indicated that mendelian dominant or codominant
models were possible. However, the analyses also suggested that a nongenetic model
fit the data as well. In addition, consistent with the familial correlations, specific
maternal- and sibling-related effects remained even after inclusion of age, gender,
and obesity covariates. These data support the concept that inheritable or shared
environmental factors contribute to the development of OSA and that maternal components
may be more important than paternal ones.
KEYWORD
obstructive sleep apnea - snoring - familial aggregation - genetics
