Bisphosphonate treatment has been described to improve survival in ENPP1-positive GACI patients, but few studies have described bisphosphonate treatment in ABCC6-positive patients.
Loss of function mutations of the ecto-nucleotide pyrophosphatase/pyrophosphodiesterase 1 gene (ENPP1) causes a wide spectrum of phenotypes, ranging from lethal generalized arterial calcification of infancy to hypophosphatemic rickets with hypertension.
In humans, variants in ENPP1 are associated with generalized arterial calcification of infancy, an autosomal-recessive condition causing premature onset of arterial calcification and intimal proliferation resulting in stenoses.
Fetal hydrops, hyperechogenic arteries and pathological doppler findings at 29 weeks: prenatal presentation of generalized arterial calcification of infancy - a novel mutation in ENPP1.
ENPP1 enzyme replacement therapy improves blood pressure and cardiovascular function in a mouse model of generalized arterial calcification of infancy.
The man alone also carried novel heterozygous missense variants within two additional genes that condition mineral homeostasis and are the basis for autosomal recessive disorders: CYP27B1 underlying vitamin D dependent rickets, type 1, and ABCC6 underlying both generalized arterial calcification of infancy, type 2 and pseudoxanthoma elasticum (PXE).
Monogenic ENPP1, CD73, and ABCC6 deficiencies each drive a molecular pathophysiology of closely related but phenotypically different diseases (generalized arterial calcification of infancy (GACI), pseudoxanthoma elasticum (PXE) and arterial calcification caused by CD73 deficiency (ACDC)), in which premature onset arterial calcification is a prominent but not the sole feature.
Heritable mutations in ABCC6 underlie the incurable calcification disorder pseudoxanthoma elasticum and some cases of generalized arterial calcification of infancy.
Thus, ABCC6 mutations account for a significant subset of GACI patients, and ENPP1 mutations can also be associated with PXE lesions in school-aged children.
Mutations in ABCC6 underlie the ectopic mineralization disorder pseudoxanthoma elasticum (PXE) and some forms of generalized arterial calcification of infancy, both of which affect the cardiovascular system.
ABCC6 mutations thus lead to reduced plasma pyrophosphate levels, resulting in the calcification disorder pseudoxanthoma elasticum and some cases of generalized arterial calcification of infancy.
Pseudoxanthoma elasticum is a prototype of heritable ectopic mineralization disorders, with phenotypic overlap with generalized arterial calcification of infancy and arterial calcification due to CD73 deficiency.
The prototype of such conditions is pseudoxanthoma elasticum, and related conditions with overlapping clinical features include generalized arterial calcification of infancy and arterial calcification due to CD73 deficiency.
Hypophosphatemia, hyperphosphaturia, and bisphosphonate treatment are associated with survival beyond infancy in generalized arterial calcification of infancy.