Complete PP is a high-risk subgroup of PP associated with higher maternal morbidity in comparison to incomplete PP.

Objective: To identify the molecular basis for prenatally suspected cases of megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) (MIM 249210) in 3 independent families with clinical and radiographic evidence of MMIHS. Methods: Whole-exome sequencing (WES) and Sanger sequencing of the ACTG2 gene. Results: We identified a novel heterozygous de novo missense variant in ACTG2 c.770G>A (p.Arg257His) encoding γ-2 smooth muscle actin (ACTG2) in 2 siblings with MMIHS, suggesting gonadal mosaicism of one of the parents. Two additional de novo missense variants (p.Arg257Cys and p.Arg178His) in ACTG2 were identified in 2 additional MMHIS patients. All of our patients had evidence of fetal megacystis and a normal or slightly increased amniotic fluid volume. Additional findings included bilateral renal hydronephrosis, an enlarged fetal stomach, and transient dilated bowel loops. ACTG2 immunostaining of the intestinal tissue showed an altered muscularis propria, a markedly thinned longitudinal muscle layer, and a reduced amount and abnormal distribution of ACTG2. Conclusion: Our study demonstrates that de novo mutations in ACTG2 are a cause of fetal megacystis in MMIHS and that gonadal mosaicism may be present in a subset of cases. These findings have implications for the counseling of families with a diagnosis of fetal megacystis with a preserved amniotic fluid volume and associated gastrointestinal findings.

Objective: To investigate prenatal ultrasonographic findings associated with megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS). Methods: A PubMed search was performed using the terms ‘MMIHS', ‘MMIH' and ‘prenatal diagnosis'. Results: A total of 50 cases were analyzed. Prenatal diagnosis was achieved in 26% of cases. In 54% of patients with a correct antenatal diagnosis there was a previously affected sibling. Fetal megacystis with or without hydroureteronephrosis was the most common initial ultrasonographic finding (88%). While megacystis eventually complicated all fetal presentations, isolated bilateral hydronephrosis and isolated dilated stomach were noted (in 10 and 2% of cases, respectively) prior to megacystis. The initial sonographic abnormality was most commonly detected (in 70% of patients) in the second trimester. Amniotic fluid was normal in 69% and increased in 27% of cases. Gastrointestinal abnormalities were noted in 24% of pregnancies. Conclusion: MMIHS should be prenatally suspected when fetal megacystis is associated with a normal or increased amount of amniotic fluid and normal external genitalia, especially in the setting of a suggestive family history. Associated gastrointestinal findings support this diagnosis. Isolated bilateral hydronephrosis may precede the development of megacystis. Due to preserved renal function and a general absence of oligohydramnios, no rationale exists for vesicoamniotic shunt placement.

We used whole exome sequence analysis to investigate a possible genetic etiology for a patient with the phenotype of intrauterine growth restriction, microcephaly, developmental delay, failure to thrive, congenital bilateral hip dysplasia, cerebral and cerebellar atrophy, hydrocephalus, and congenital diaphragmatic hernia (CDH). Whole exome sequencing identified a novel de novo c.2722G > T (p.E908X) mutation in the Myosin Heavy Chain 10 gene (MYH10) which encodes for non-muscle heavy chain II B (NMHC IIB). Mutations in MYH10 have not been previously described in association with human disease. The E908X mutation is located in the coiled-coil region of the protein and is expected to delete the tail domain and disrupt filament assembly. Nonmuscle myosin IIs (NM IIs) are a group of ubiquitously expressed proteins, and NM II B is specifically enriched in neuronal tissue and is thought to be important in neuronal migration. It is also expressed in cardiac myocytes along with NM IIC. Homozygous NMHC II B-/B- mouse knockouts die by embryonic day (E)14.5 with severe cardiac defects (membranous ventricular septal defect and cardiac outflow tract abnormalities) and neurodevelopmental disorders (progressive hydrocephalus and neuronal migrational abnormalities). A heterozygous MYH10 loss of function mutation produces a severe neurologic phenotype and CDH but no apparent cardiac phenotype and suggests that MYH10 may represent a novel gene for brain malformations and/or CDH.

Congenital cystic lung lesions (CCLL) are a group of rare pathologies that are usually diagnosed in the pre-natal period. The majority of these lesions are diagnosed at pathology examination as congenital pulmonary airway malformations (CPAM) and bronchopulmonary sequestration (BPS). These lesions are typically managed by surgical intervention within the first year of life and have an excellent prognosis. We examined the evolution of imaging appearances from prenatal diagnosis to postnatal work-up of these lesions and correlate imaging and pathological findings. An 8-year retrospective review of the perinatal and pathology database of a single tertiary care center identified 42 cases of CCLL of which 36 had known prenatal ultrasound and prenatal course available. Final pathologic diagnoses were: 15 CPAM (41%), 7 BPS (19%) and 9 hybrid BPS and CPAM lesions (25%). Five cases with bronchial atresia were also identified (either in isolation or associated with CPAM or BPS). The overall characteristics of these lesions by prenatal ultrasound, postnatal imaging, and ultimate histopathologic diagnosis are described.

Objectives-To assess the diagnostic performance of the fetal cardiac axis (CA) and/or cardiac position (CP) versus the congenital pulmonary malformation volume ratio (CVR) in predicting any and severe neonatal respiratory morbidity in fetal congenital lung lesions.Methods-This work was an 11-year retrospective cohort study. The sensitivity, specificity, positive predictive value, and negative predictive value of CA and/or CP assessment in prediction of respiratory morbidity were calculated before 24 weeks' gestation and between 24 and 32 weeks and compared to CVR cutoffs obtained from the literature.Results-Fifty-three patients were included. CA and/or CP abnormalities were present in 45% and 38% of patients before 24 weeks and between 24 and 32 weeks and were significantly more common in left-versus rightsided lesions (60% versus 17%; P = .003). The sensitivity, specificity, positive predictive value, and negative predictive value of an abnormal CA and/or CP for any and severe respiratory morbidity were 0.67, 0.61, 0.33, and 0.86 and 0.8, 0.58, 0.17, and 0.97 before 24 weeks and 0.75, 0.73, 0.45, and 0.91 and 0.8, 0.67, 0.20, and 0.97 between 24 and 32 weeks, respectively. An abnormal CA and/or CP had higher sensitivity for any respiratory morbidity compared to the CVR at 0.5 and 0.8 cutoffs both before 24 weeks and between 24 and 32 weeks (P < .05).Conclusions-An abnormal CA and/or CP before 24 weeks and between 24 and 32 weeks has higher sensitivity for the detection of any respiratory morbidity at birth compared to the CVR at both 0.5 and 0.8 cutoffs. A normal CA and CP have a high negative predictive value for excluding any respiratory morbidity at birth both before 24 weeks and between 24 and 32 weeks.

Congenital cystic lung lesions are a group of rare pathologies that are usually diagnosed in the prenatal period. The majority of these lesions are diagnosed at pathology examination as congenital pulmonary airway malformations (CPAM) and bronchopulmonary sequestration (BPS). These lesions are typically managed by surgical intervention within the first year of life and have an excellent prognosis. We examined the evolution of imaging appearances from prenatal diagnosis to postnatal work-up of these lesions and correlate imaging and pathological findings. An 8-year retrospective review of the perinatal and pathology database of a single tertiary care center identified 42 cases of congenital cystic lung lesions of which 36 had known prenatal ultrasound and prenatal course available. Final pathologic diagnoses were 15 CPAM (41%), 7 BPS (19%), and 9 hybrid BPS and CPAM lesions (25%). Five cases with bronchial atresia were also identified (either in isolation or associated with CPAM or BPS). The overall characteristics of these lesions by prenatal ultrasound, postnatal imaging, and ultimate histopathologic diagnosis are described.

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