Biallelic Variants in MNS1 Are Associated with Laterality Defects and Respiratory Involvement.

Defects in motile cilia, termed motile ciliopathies, result in clinical manifestations affecting the respiratory and reproductive system, as well as laterality defects and hydrocephalus. We previously defined biallelic MNS1 variants causing situs inversus and male infertility, mirroring the findings in Mns1-/- mice. Here, we present clinical and genomic findings in five newly identified individuals from four unrelated families affected by MNS1-related disorder. Ciliopathy panel testing and whole exome sequencing identified one previously reported and two novel MNS1 variants extending the genotypic spectrum of disease. A broad spectrum of laterality defects including situs inversus totalis and heterotaxia was confirmed. Interestingly, a single affected six-year-old girl homozygous for an MNS1 nonsense variant presented with a history of neonatal respiratory distress syndrome, recurrent respiratory tract infections, chronic rhinitis, and wet cough. Accordingly, immunofluorescence analysis showed the absence of MNS1 from the respiratory epithelial cells of this individual. Two other individuals with hypomorphic variants showed laterality defects and mild respiratory phenotype. This study represents the first observation of heterotaxia and respiratory disease in individuals with biallelic MNS1 variants, an important extension of the phenotype associated with MNS1-related motile ciliopathy disorder.

Recessively Inherited Deficiency of Secreted WFDC2 (HE4) Causes Nasal Polyposis and Bronchiectasis.

Rationale: Bronchiectasis is a pathological dilatation of the bronchi in the respiratory airways associated with environmental or genetic causes (e.g., cystic fibrosis, primary ciliary dyskinesia, and primary immunodeficiency disorders), but most cases remain idiopathic. Objectives: To identify novel genetic defects in unsolved cases of bronchiectasis presenting with severe rhinosinusitis, nasal polyposis, and pulmonary Pseudomonas aeruginosa infection. Methods: DNA was analyzed by next-generation or targeted Sanger sequencing. RNA was analyzed by quantitative PCR and single-cell RNA sequencing. Patient-derived cells, cell cultures, and secretions (mucus, saliva, seminal fluid) were analyzed by Western blotting and immunofluorescence microscopy, and mucociliary activity was measured. Blood serum was analyzed by electrochemiluminescence immunoassay. Protein structure and proteomic analyses were used to assess the impact of a disease-causing founder variant. Measurements and Main Results: We identified biallelic pathogenic variants in WAP four-disulfide core domain 2 (WFDC2) in 11 individuals from 10 unrelated families originating from the United States, Europe, Asia, and Africa. Expression of WFDC2 was detected predominantly in secretory cells of control airway epithelium and also in submucosal glands. We demonstrate that WFDC2 is below the limit of detection in blood serum and hardly detectable in samples of saliva, seminal fluid, and airway surface liquid from WFDC2-deficient individuals. Computer simulations and deglycosylation assays indicate that the disease-causing founder variant p.Cys49Arg structurally hampers glycosylation and, thus, secretion of mature WFDC2. Conclusions: WFDC2 dysfunction defines a novel molecular etiology of bronchiectasis characterized by the deficiency of a secreted component of the airways. A commercially available blood test combined with genetic testing allows its diagnosis.

Polimorfismo rs5370 del gen de la endotelina-1 en el síndrome nefrótico primario: estudio de casos y controles / Endothelin-1 rs5370 gene polymorphism in primary nephrotic syndrome: A case-control study

Introducción: El síndrome nefrótico (SN) primario es una glomerulopatía común en la edad pediátrica. Se evaluaron los genotipos y frecuencias alélicas del polimorfismo rs5370 del gen EDN1 en niños con SN primario.Pacientes y métodos: Estudio de casos y controles realizado en el Hospital Infantil Universitario de El Mansura, Egipto, de diciembre de 2015 a enero de 2018. Se seleccionó a 50 pacientes con SN corticosensible (SNCS) y a 50 con SN corticorresistente (SNCR), así como a 100 controles sanos. Además de una evaluación clínica de los pacientes, se hicieron pruebas de cuantificación de albúmina, colesterol, creatinina y urea séricas y de proteinuria en muestra de orina de 24 h. Se emplearon técnicas de reacción en cadena de la polimerasa para analizar los genotipos (GG, GT y TT) y los alelos (T y G) del polimorfismo rs5370 del gen EDN1 en los grupos en estudio.Resultados: El genotipo GT fue el más frecuente del polimorfismo rs5370 del gen EDN1 en el grupo de control (88%, p=0,001), mientras que el genotipo GG fue más frecuente en el grupo con SN que en el de control (p=0,02). No se encontraron diferencias estadísticamente significativas entre los grupos de SN y de control en los alelos del polimorfismo rs5370 (p=0,69). El genotipo GG fue más prevalente en el grupo de SNSC que en los grupos de SNRC y de control (p=0,03). Las diferencias en las frecuencias alélicas entre los grupos de SNRC, SNSC y de control no fueron significativas (p=0,89). El genotipo GT se asoció a una presión arterial normal en niños con SN (p=0,007) mientras que el genotipo GG se asoció a hipertensión (p<0,001). No se detectaron diferencias significativas en la histopatología renal ni en los niveles séricos de colesterol respecto al genotipo.Conclusiones: El genotipo GG del polimorfismo rs5370 del gen EDN1 podría asociarse a un riesgo mayor de desarrollar SN y a una respuesta más favorable al tratamiento con corticoides. (AU)

Introduction: Primary nephrotic syndrome (NS) is a common glomerular disease in children. We assessed the genotypes and frequency of the rs5370 allelic variant of the EDN1 gene in children with primary NS.Patients and methods: We conducted a case-control study in Mansoura University Children's Hospital, Egypt, between December 2015 and January 2018. We recruited 50 patients with steroid-sensitive NS (SSNS) and 50 patients with steroid-resistant NS (SRNS) in addition to 100 healthy controls. The patients underwent clinical evaluations and tests including measurement of serum albumin, cholesterol, creatinine and urea levels and a 24-hour urinary protein test. We used polymerase chain reaction methods to assess the genotypes of rs5370 variants of the EDN1 gene (GG, GT and TT) and alleles (T and G) in the groups under study.Results: The most frequent genotype of the EDN1 gene at the locus of interest in the control group was the GT genotype (88%; P=.001) while the GG genotype was more frequent in the NS group compared to the control group (P=.02). We did not find statistically significant differences between the NS and control groups in regard to the EDN1 rs5370 alleles (P=.69). The GG genotype was more frequent in the SSNS group compared to the SRNS and control groups (P=.03). When we compared allele frequencies between the control, SSNS and SRNS groups, we did not find significant differences (P=.89). The GT genotype was associated with normal blood pressure in children with NS (P=.007), while the GG genotype was associated with hypertension (P<.001). We did not find statistically significant differences in renal histopathology or serum cholesterol levels based on the genotype.Conclusions: The GG genotype at the rs5370 locus of the EDN1 gene may be associated with an increased risk of primary NS and a better response to steroid therapy. (AU)