[Persistent hypertension for two months in a preterm infant]

A boy aged 2 months (born at 36 weeks of gestation) was admitted due to cough and dyspnea. After admission, he was found to have persistent hypertension, proteinuria, and persistent convulsion, and imaging examination showed extensive calcification of the aorta and major branches and stenosis of local lumens of the abdominal aorta and the right renal artery with increased blood flow velocity. The boy was admitted during the neonatal period due to wet lung and pulmonary arterial hypertension and was found to have hypertension and proteinuria. High-throughput whole-exome sequencing was performed and found two compound heterozygous mutations in the ENPP1 gene from his parents, c.130C>T (p.Q44X) and c.1112A>T (p.Y371F). c.130C>T was a nonsense mutation, which could cause partial deletion of protein from 44 amino acids, and was defined as a primary pathogenic mutation. c.1112A>T was a missense mutation which had been reported as a pathogenic mutation associated with idiopathic infantile arterial calcification (IIAC). Therefore, he was diagnosed with IIAC. He was given phosphonate drugs, antihypertensive drugs, anticonvulsion treatment, and respiratory support. Blood pressure was maintained at the upper limit of normal value. There was no deterioration of arterial calcification. It is concluded that IIAC should be considered for infants with persistent hypertension and extensive vascular calcification, and imaging and genetic examinations should be performed as early as possible to make a confirmed diagnosis.