Abstract 16747: Rapidly Lethal Dilated Cardiomyopathy Secondary To Generalized Arterial Calcification Of Infancy

Case Presentation: A previously healthy 3-month-old infant presented with cardiorespiratory arrest, from which she was successfully resuscitated. A dilated cardiomyopathy with severely depressed systolic function was diagnosed. ECG showed high voltage QRS complexes and generalized alteration of repolarization. In the following 12 hours, she suffered 2 other cardiac arrests, recuperated with defibrillation. Hemodinamic stability was achieved but brain death was diagnosed 36 hours after the onset of symptoms. Autopsy showed striking calcification of the right and left coronary arteries, with narrowing of the arterial lumen, causing extensive subendocardial infarction. Calcification also affected the aorta, pulmonary arteries, thyroid, kidney and other splanchnic arteries. Generalized arterial calcification of infancy (GACI) was diagnosed and a genetic study found two biallelic variants in ABCC6 gene: p.Arg1114Cys and p.Trp38Ser, both previously described in elastic pseudoxanthoma (PXE), but not in GACI. Genotyping of the healthy parents confirmed genetic segregation with biallelic variants. Discussion: GACI is an extremely rare genetic disease characterized by widespread arterial calcification and narrowing of large and medium-sized vessels. The usual clinical presentation is heart failure in fetal life or in the first months of infancy. In most cases it is lethal, with death occurring within a few hours or days after the onset of symptoms, although clinical involvement is highly variable and cases with long survival have been described. GACI is an autosomal recessive disease secondary to biallelic variants in the ENPP1 gene (67% of cases) and in the ABCC6 gene (9%). The variants found in our patient had not been previously described in GACI, just in PXE, a much milder disease with usually normal lifespan. This case confirms that both entities reflect two extremes of a clinical spectrum of ectopic calcification instead of two different disorders. The aim of presenting this case is to remind clinicians of this rare etiology in neonates or infants with dilated cardiomyopathy. In case of death, autopsy should always be requested. When this condition is diagnosed, genetic study will be positive in 75% of cases, allowing prenatal counseling.