Editor—Isolated congenital diaphragmatic hernia (ICDH) may be sporadic or familial. The mode of inheritance in familial cases (IFCDH) is a matter for debate and different patterns have been proposed. For example, multifactorial inheritance was suggested by Wolff1 and by Norio et al.2 However, autosomal recessive inheritance has been suggested in clinical studies3-6 and also in animal studies.7 8 Also, there have been various families reported to date in which other patterns of inheritance are possible (table 1).

If all the published pedigrees with familial CDH are analysed, autosomal dominant, autosomal recessive, and X linked inheritance patterns can be seen. We propose a hypothesis which unifies these various mechanisms, which is to consider imprinting as involved in the inheritance pattern of this condition.

In 1994, two non-consanguineous girls with isolated CDH and balanced translocations involving 8q22.3 were reported by Templeet al.14 …