Possible multifactorial etiology of isolated microtia/anotia--a population-based study
László Paput1, Andrew E Czeizel, Ferenc Bánhidy
1Department of Oto-Rhino-Laryngologic and Head/Neck Surgical Department, National Center for Healthcare Audit and Improvement, Budapest, Hungary. barabas.ev@gmail.com
Objective:
To test the possible multifactorial-threshold model in the origin of isolated microtia/anotia (IMA).
Method:
The observed number of IMA in the first degree relatives of cases affected was compared with the expected number of affected first degree relatives based on the multifactorial-threshold model in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996.
Results:
Of 354 cases with IMA, 14 (4.0%) had the affected first degree relatives with IMA. There was a low and similar rate of familial occurrence of IMA in parents and siblings of cases. The observed numbers of affected first degree relatives of cases with IMA and their expected numbers did not show significant difference (p=0.47). Some other findings (e.g. male excess and the interaction of triggering environmental factors with polygenic predisposition) confirmed this hypothesis.
Conclusions:
The familial pattern of cases with IMA does not reject the hypothesis that the multifactorial-threshold model, i.e. gene-environmental interaction, may be the explanation for the origin of this congenital abnormality group, although the number of familial cases was quite small in the study.
Insights
The multifactorial-threshold model, involving gene-environmental interactions, may explain isolated microtia/anotia (IMA). Familial occurrence rates in relatives did not significantly differ from expected, supporting this genetic and environmental influence hypothesis for IMA.
Area of Science:
- Medical Genetics
- Developmental Biology
- Public Health
Background:
- Isolated microtia/anotia (IMA) is a congenital abnormality with unclear etiology.
- Understanding the genetic and environmental factors contributing to IMA is crucial for prevention and management.
Purpose of the Study:
- To evaluate the multifactorial-threshold model as an explanation for the occurrence of isolated microtia/anotia (IMA).
Main Methods:
- A population-based dataset from the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980-1996) was utilized.
- The observed frequency of IMA in first-degree relatives of affected cases was compared to expected frequencies predicted by the multifactorial-threshold model.
Main Results:
- Among 354 IMA cases, 14 (4.0%) had affected first-degree relatives.
- Observed familial occurrence rates were low and similar in parents and siblings.
- No significant difference was found between observed and expected numbers of affected relatives (p=0.47).
- Findings such as male excess and potential gene-environmental interactions supported the multifactorial hypothesis.
Conclusions:
- The familial pattern of IMA is consistent with the multifactorial-threshold model, suggesting a combination of genetic predisposition and environmental factors.
- While the study supports the gene-environmental interaction hypothesis for IMA, the small number of familial cases warrants cautious interpretation.
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