The majority of cases of Duane syndrome are sporadic (occurring in individuals with no history of the condition in the family). About 10% of affected individuals appear to have other affected family members. Both autosomal dominant (most commonly) and autosomal recessive forms of Duane syndrome have been documented. In some families with dominant Duane syndrome, it has appeared to "skip a generation" (showing reduced penetrance) and it has also been shown to range in severity within the same family (showing variable expressivity). Most familial cases are not associated with other anomalies. Given the large percentage of sporadic cases, it seems likely that both genetic and environmental factors play a role in the development of Duane syndrome amongst affected individuals.
Last updated: 3/21/2012
What is the probability of passing Duane syndrome on to my future offspring?
Most individuals with isolated Duane syndrome (having no other features or underlying disorder) are simplex cases (i.e., a single occurrence in a family) of unknown cause. However, up to 10% of cases of Duane syndrome are familial,, and may result from mutations in the CHN1 gene; these cases are inherited in an autosomal dominant manner with incomplete penetrance. Each child of an individual with Duane syndrome that is known to result from a CHN1 mutation has a 50% chance of inheriting the condition. However, a large degree of clinical variability exists with this condition, so not all individuals who are affected will have the same type or degree of symptoms. Prenatal diagnosis is possible for pregnancies at increased risk for isolated Duane syndrome if the mutation has been identified in an affected family member.
Individuals hoping to gain a better understanding of the specific risk posed to their offspring should consult with a genetics professional.
Last updated: 3/3/2011
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