[Alveolar capillary dysplasia with misalignment of the pulmonary veins: a case report and literature review].

To investigate the clinical, pathological and genetic characteristics of neonatal alveolar capillary dysplasia with misalignment of the pulmonary veins (ACDMPV). The clinical manifestations, radiographic examinations, pathology and parental genetic analysis of a newborn with FOXF1 variation induced ACDMPV, who was hospitalized in the Department of Neonatology of Shenzhen Children's Hospital in January 2020, were extracted and analyzed. Related literature up to March 2020 with the key words of "Alveolar capillaries dysplasia" "Alveolar capillary dysplasia with misalignment of the pulmonary veins" "FOXF1" in PubMed, CNKI, Wanfang, CQVIP database and Leiden Open Variation database (LOVD) were searched. A full-term male newborn （1 hour of age） was admitted due to anal atresia. Surgical repair of anal atresia and omphalocele was performed on the first day of life, and gallbladder absence and Meckel's diverticulum were identified during the operation. Respiratory distress with hypoxemia developed at about 6 hours of life, and persistent pulmonary hypertension developed and progressed after surgery, with poor response to mechanical ventilation and pulmonary vasodilators. This infant passed away at 26 days of life. Lung biopsy showed decreased alveolar units and thickened interalveolar septa, reduced alveolar capillary density and thickened walls of peripheral pulmonary arteries, and misaligned pulmonary veins adjacent to the pulmonary arterioles, which were consistent with ACDMPV. The whole exome sequencing revealed a heterozygous novel frameshift of FOXF1 gene located in chromosome 16q24.1 c376_377insT; p.(Pro126fs). According to the bioinformatics analysis, this variation was likely to be pathogenic as it was associated with coding disorder of FOXF1 Pro126, resulting in truncation of the encoded protein. This novel variation had not been reported in the human gene mutation database (HGMD), ESP6500siv2_ALL, 1000g2015aug_ALL or dbSNP147 database. Previous 6 literatures reported 54 variants, including 28 missense, 10 nonsense, 11 frameshift, 2 deletion, 1 synonymous, and 2 extensions. Only three of the reported 45 cases （24 males, 21 females） were still alive as of the time of this study. Typically, ACDMPV is a catastrophic disease in neonatal period with high mortality. Lung biopsy and genetic testing should be considered in infants who present with persistent pulmonary hypertension and refractory hypoxemia, especially when combined with extrapulmonary abnormalities.