The objective of the study is to investigate congenital disorders of glycosylation in congenital heart diseases without a clear molecular or genetic basis.

Congenital disorders of glycosylation (CDG) are a family of inherited disorders caused by defects in the synthesis of glycans, glycoproteins or other glycoconjugates. Congenital disorders of glycosylation (CDG) are a family of inherited disorders caused by defects in the synthesis of glycans, glycoproteins or other glycoconjugates. Glycosylation of proteins is crucial for a proper organ morphogenesis and for an appropriate coagulation system functioning. The neurological system is commonly affected in this type of disorders but cases of CDG with normal neurological development have been recently described. The group of Experimental Hematology and Clinic Oncology of the University of Murcia (Spain) recently described a rare disorder of glycosylation (ALG12-CDG) as the cause of antithrombin deficiency in a patient of 19 years with a history of repaired ventricular septal defect.

On the other hand, population studies have shown an increased incidence of thromboembolic events in patients with congenital heart disease when compared to the general population. The identified genetic defects involved in the development of congenital heart diseases have variable or incomplete penetrance and in most cases the molecular basis is completely unknown.

The investigators postulate that a CDG might be behind the development of some forms of congenital heart disease and contribute to the greater prevalence of thromboembolic events in this patient population.

Inclusion Criteria:

• Adult with a congenital heart disease with most probability to present a congenital disorder of glycosylation of proteins

Exclusion Criteria:

• Denial of informed consent.

250-300 adult patients who are most likely to have a congenital disorder of glycosylation of proteins, such as ventricular and atrial septal defects and especially conotruncal defects