Not all genetic disorders are caused from cousin marriages some just require 1 gene from any parent...
While sometimes even a random match causes problem...My uncle and aunt are an example...Only sibling out of 6 (uncle) married a non relative and he is the only 1 who seems to have 2 kids with some congenital defects...
I know that, but it increases the risk.
Like the risk of Situs Invertus( Where the organs are on the opposite side) condition, with which this baby was born has a high percentage of occurrence in kids born out of cousin marriages.
The exact inheritance pattern in familial dextrocardia is not completely understood; Campbell3 studied 21 sibs of 10 families with situs inversus and reported the importance of consanguinity while Cockayne4 reported several members of same family affected with situs inversus and further noted a high percentage of its occurrence in marriages involving first cousins; he then suggested an autosomal recessive mode of inheritance, however the documentation of dextrocardia in two successive generations as observed by Chib et al.,5 may suggest an autosomal dominant mode of inheritance in some cases; however, in our case, both parents were not affected and they were first cousins, while the second wife, who was not related to the husband, recently had a child who was also not affected, which may further buttress the significance of consanguinity and an autosomal recessive mode of inheritance.
Familial dextrocardia in a Nigerian family