Chromosome 17q23.1-q23.2 deletion syndrome with severe pulmonary hypertension in neonates: two case reports and literature review

Chromosome 17q23.1-q23.2 deletion syndrome is a rare genetic disorder characterized by various congenital defects, including microcephaly, heart and lung defects, limb abnormalities, and mild-to-severe developmental delay. Respiratory distress and severe pulmonary hypertension (PH) are possible initial symptoms. We report two cases of full-term neonates with respiratory distress presenting shortly after birth. They both presented with severe PH in the early postnatal period, with oxygenation indices exceeding 70. Their symptoms were temporarily relieved with comprehensive treatment but PH either persisted into, or reappeared in infancy. Case 1 had an anomalous origin of the right upper lobe bronchus on chest computed tomography (CT) imaging, while Case 2 had an atrial septal defect and cor triatriatum sinister on echocardiography. Case 2 also exhibited bilateral inner ear malformations and bilateral irregularities in the morphology of the auditory ossicles on temporal bone CT imaging. Whole-exome sequencing revealed a 2.0-2.3 Mb de novo heterozygous deletion at 17q23.1-q23.2 encompassing T-box transcription factor 2 and 4 genes in both infants, which were confirmed by quantitative real-time PCR. Despite receiving intensive care, they succumbed to irreversible PH and respiratory and heart failure, with one passing away at 3 months and the other at 20 months of age. This is the first report of two cases of chromosome 17q23.1-q23.2 deletion syndrome diagnosed after birth in China, both associated with intractable PH, expanding the current clinical phenotype spectrum of this disorder.