This molecular result has led to three different hypotheses: (1) the possibility that the proband could harbor another variant in a portion of SEC23A gene that is undetectable due to low coverage detection rate (e.g., an intronic region); (2) the suspicion of digenic inheritance since the patient had a missense variant in SEC23A and potentially a second mutation in another COPII subunit or cargo molecule; (3) the suggestion that CLSD might also have an autosomal dominant inheritance with incomplete penetrance beyond the known AR-CLSD. Here, SEC23A is linked to craniolenticulosutural dysplasia.