Homozygous loss-of-function mutations in MNS1 cause laterality defects and likely male infertility.

The clinical spectrum of ciliopathies affecting motile cilia spans impaired mucociliary clearance in the respiratory system, laterality defects including heart malformations, infertility and hydrocephalus. Using linkage analysis and whole exome sequencing, we identified two recessive loss-of-function MNS1 mutations in five individuals from four consanguineous families: 1) a homozygous nonsense mutation p.Arg242* in four males with laterality defects and infertility and 2) a homozygous nonsense mutation p.Gln203* in one female with laterality defects and recurrent respiratory infections additionally carrying homozygous mutations in DNAH5. Consistent with the laterality defects observed in these individuals, we found Mns1 to be expressed in mouse embryonic ventral node. Immunofluorescence analysis further revealed that MNS1 localizes to the axonemes of respiratory cilia as well as sperm flagella in human. In-depth ultrastructural analyses confirmed a subtle outer dynein arm (ODA) defect in the axonemes of respiratory epithelial cells resembling findings reported in Mns1-deficient mice. Ultrastructural analyses in the female carrying combined mutations in MNS1 and DNAH5 indicated a role for MNS1 in the process of ODA docking (ODA-DC) in the distal respiratory axonemes. Furthermore, co-immunoprecipitation and yeast two hybrid analyses demonstrated that MNS1 dimerizes and interacts with the ODA docking complex component CCDC114. Overall, we demonstrate that MNS1 deficiency in humans causes laterality defects (situs inversus) and likely male infertility and that MNS1 plays a role in the ODA-DC assembly.

Immune-Mediated Fetal Complete Atrioventricular Block: Can Dexamethasone Therapy Revert the Process?

BACKGROUND: Fetal complete atrioventricular block (CAVB) is usually autoimmune mediated. The risk of developing CAVB is 2% to 3% in anti-Ro/SS-A seropositive pregnancies and it increases 10 times after previous CAVB in siblings. Despite being a rare complication, CAVB carries a 20% mortality rate and substantial morbidity, as about 65% of newborns will eventually need life-long pacing. Once found, fetal CAVB is almost always irreversible, despite aggressive immunotherapy. This poor outcome prompted some research groups to address this situation. All groups followed anti-Ro/SS-A seropositive pregnancies on a weekly basis during the second trimester of pregnancy and tried to detect first degree atrioventricular block (AVB) using accurate echocardiographic tools, assuming they may characterize the initiation of the immune damage to the A-V conduction system, at which point the process might still be reversible. Some of the groups treated fetuses with first degree AVB with maternal oral fluorinated steroids. We summarized the results of all groups, including our group. We describe a case of a fetus that developed CAVB 6 days after normal sinus rhythm (NSR), who under aggressive dexamethasone therapy gradually reverted to NSR. This fetus had a previous sibling with CAVB. We assumed the immune damage to the conduction system in this small group of fetuses with a previous CAVB sibling may have occurred more quickly than usual. We therefore recommend a twice-weekly follow-up with these fetuses.

Punch-out lesion following regression of a large left ventricular outflow rhabdomyoma.

Abstracts We report the case of a patient with rhabdomyoma of the left ventricular outflow tract, causing severe obstruction at birth. The tumour regressed completely by 6 years of age, leaving a punch-out lesion. The potential for spontaneous regression of these tumours and the formation of a myocardial lesion following rhabdomyoma regression are discussed.

Transcatheter Management of Pulmonary Sequestrations in Children-A Single-Center Experience.

BACKGROUND: A pulmonary sequestration (PS) is an area of bronchopulmonary tissue with aberrant arterial supply. Transcatheter occlusion of PSs is an appealing treatment option, but data on outcomes remain scarce. We aim to describe our experience with transcatheter management of PS in infants and children. METHODS: Retrospective review of clinical data of all patients with suspected PS sent for diagnostic and/or interventional cardiac catheterization at our institution between January 1999 and May 2021. Procedural considerations, techniques, standard safety, and outcomes were assessed. RESULTS: We identified 71 patients (52.1% males), with median age and weight of 4.9 months (IQR, 2.1-26.6) and 4.2 kg (IQR, 3.9-12.1), respectively. Sixty-one (86%) patients had associated congenital heart defects (CHDs). Forty-two (59%) patients had pulmonary arterial hypertension (PAH) at the time of diagnosis. Fifty-three (74.7%) patients underwent embolization of the PS feeding vessel using microcoils and/or vascular plugs, and eight (15.1%) of these were neonates who presented with severe PAH and cardiac failure. Two patients had large feeding vessels and were treated surgically. Sixteen (22.5%) patients with small feeding vessels received conservative management. At median follow-up of 36.4 months (IQR, 2.1-89.9), seven patients had died, 24 patients had CHD corrective surgeries, 26 patients had redo catheterizations, and five patients had persistent PAH. No PS surgical resection was needed, and no infection of the remaining lung tissue occurred. CONCLUSIONS: Transcatheter assessment and treatment of PSs is a safe and effective procedure. Neonates with large PSs are severely symptomatic and improve remarkably after PS closure. PS embolization and surgical repair of associated CHDs generally leads to the normalization of pulmonary pressures.

A New Solution for Stenting Large Right Ventricular Outflow Tracts Before Transcatheter Pulmonary Valve Replacement.

BACKGROUND: Prestenting right ventricular outflow tracts (RVOTs) before transcatheter pulmonary valve replacement (TPVR) is essential. Optimus-XXL (AndraTec GmbH, Koblenz, Germany) is a new extra-large, balloon-expandable cobalt-chrome stent with promising technologies. METHODS: From June 2020 to November 2020, 15 patients with congenital heart disease, dysfunctional RVOTs and target TPVR diameter ≥ 23 mm received Optimus-XXL stents before proceeding to TPVR using the SAPIEN valve (Edwards Lifesciences, Irvine, CA). Standard safety and outcomes were prospectively assessed. RESULTS: Patients' median age and weight were 25.8 years (range: 10.5-63.1 years) and 58 kg (range: 43.8-101 kg), respectively. Underlying diagnosis was tetralogy of Fallot (66.7%), and RVOTs were patched (80%). Fifteen bare-metal stents were implanted using femoral (n = 14) and jugular approaches (n = 1). One conduit rupture was immediately controlled with a covered Optimus-XXL. Median stent length was 43 mm (range: 33-57 mm), and median target expansion diameter was 28 mm (range: 23-30 mm). Two procedural incidents occurred during stent delivery and were percutaneously treated. Stent stability was documented during TPVRs immediately performed in 14 patients. Median stent shortening was 13.7%, and median percentage of intended stent expansion was 95.9%. There was no stent fracture on the short-term follow-up (median: 4.5 months). CONCLUSIONS: We report the first implantations of Optimus-XXL stents in dysfunctional RVOTs with excellent preliminary results. Optimus-XXL should be considered as a valuable adjunct in the armamentarium for routine and complex TPVR procedures.

Spontaneous Closure of the Arterial Duct after Transcatheter Closure Attempt in Preterm Infants.

(1) Background: Transcatheter closure of the patent arterial duct (TCPDA) in preterm infants is an emerging procedure. Patent arterial duct (PDA) spontaneous closure after failed TCPDA attempts is seen but reasons and outcomes are not reported; (2) Methods: We retrospectively included all premature infants <2 kg with abandoned TCPDA procedures from our institutional database between September 2017 and August 2021. Patients' data and outcomes were reviewed; (3) Results: The procedure was aborted in 14/130 patients referred for TCPDA. Two patients had spasmed PDA upon arrival in the catheterization laboratory and had no intervention. One patient had ductal spasm after guidewire cross. Four patients had unsuitable PDA size/shape for closure. In seven patients, device closure was not possible without causing obstruction on adjacent vessels. Among the 12 patients with attempted TCPDA, five had surgery on a median of 3 days after TCPDA and seven had a spontaneous PDA closure within a median of 3 days after the procedure. Only the shape of the PDA differed between the surgical ligation group (short and conical) and spontaneous closure group (F-type); (4) Conclusions: In the case of TCPDA failure, mechanically induced spontaneous closure may occur early after the procedure. Surgical ligation should be postponed when clinically tolerated.