Clinical phenotype characteristics and genetic analysis in children with nephronophthisis and related syndromes caused by different gene mutations / 中国当代儿科杂志

OBJECTIVES@#To improve the understanding of the clinical phenotypes and genetic characteristics of nephronophthisis (NPHP) and related syndromes in children.@*METHODS@#A retrospective analysis was performed on the medical data of eight children with NPHP and related syndromes who were diagnosed and treated in the Department of Pediatrics of the Second Hospital of Hebei Medical University, from January 2018 to November 2022. The clinical characteristics and genetic testing results were analyzed.@*RESULTS@#Among these eight children, there were five boys and three girls, with an age of onset ranging from 15 months to 12 years. All 8 children exhibited different degrees of renal function abnormalities when they attended the hospital. Among the eight children, two had the initial symptom of delayed development, two had the initial symptom of anemia, and two were found to have abnormal renal function during physical examination. The extrarenal manifestations included cardiovascular abnormalities in two children, skeletal dysplasia in two children, liver dysfunction in one child, retinitis pigmentosa in one child, and visceral translocation in one child. All eight children had renal structural changes on ultrasound, and four children had mild to moderate proteinuria based on routine urine test. Of all eight children, five had NPHP1 gene mutations and one each had a gene mutation in the NPHP3, IFT140, and TTC21B genes, and four new mutation sites were discovered.@*CONCLUSIONS@#Children with NPHP and related syndromes often have the initial symptom of delayed development or anemia, and some children also have extrarenal manifestations. NPHP and related syndromes should be considered for children with unexplained renal dysfunction, and high-throughput sequencing may help to make a confirmed diagnosis.

Clinical phenotype and genotype analysis in 9 children with nephronophthisis / 中华肾脏病杂志

Objective:To investigate and analyze the clinical phenotypes and genotypes in children diagnosed with nephronophthisis (NPHP), and to provide references for clinical diagnosis.Methods:Clinical data of 9 children with NPHP diagnosed by genetic testing in the Department of Nephrology, Wuhan Children′s Hospital from April 2017 to January 2022 were retrospectively collected. The clinical characteristics and genetic test results were analyzed.Results:The median onset age was 11.2(3.4, 14.2) years old in 9 patients, including 5 females and 4 males. There were 8 cases of glomerular proteinuria, 8 cases of renal tubular proteinuria, and 7 cases of reduced urinary gravity in 9 patients. All the children had varying degrees of impaired renal function at the time of diagnosis. Seven cases entered chronic kidney disease (CKD) stage 5, 1 case entered CKD stage 3, and 1 case entered CKD stage 4 at the time of diagnosis. All the children had renal ultrasound abnormalities of varying degrees: size change (3/9), echo enhancement (8/9) and cysts (3/9). Extrarenal phenotypes were present in 3 children. Genetic test showed that 6 patients had mutation of NPHP1 gene, 1 patient had mutation of WDR19 gene, 1 patient had mutation of NPHP3 gene and 1 patient had mutation of NPHP5 gene. Conclusions:Deletion mutation of NPHP1 gene is the most common, while NPHP3, NPHP5 and extremely rare WDR19 mutations have also been found in NPHP patients. The clinical manifestations of NPHP are not typical, so it is necessary to find a specific diagnosis method in the early.

Progress in genetics of NPHP related signaling pathway / 国际儿科学杂志

Nephronophthisis(NPHP),an autosomal recessive cystic kidney disease,is the most frequent genetic cause for end stage renal failure in the first thirty years of life.NPHP can be caused by Mutations in 22 genes(NPHP1-20,NPHPL1,NPHPL2),with abnormal structure or function of primary cilia,involved in Hh,Wnt,Hippo,DDR signaling pathways.Elucidating the pathogenic genes and possible pathogenesis would make a difference in prevention,diagnosis,treatment,prognosis,and genetic counseling of NPHP.This article reviews the pathogenic genetics and related signaling pathways.

NPHP1 knockdown induces epithelial-mesenchymal transition in Madin-Darby canine kidney cells / 中华肾脏病杂志

Objective To explore the impacts of NPHP1 knockdown on the phenotype of Madin-Darby canine kidney (MDCK) cells. Methods The expression of NPHP1 in MDCK cells was knockdown by siRNA interference. Cells were divided into normal control group, negative control group and siRNA group. The cellular morphology and migration were observed by light microscope. The mRNA expressions and activities of matrix metalloproteinases 2 and 9 (MMP2 and MMP9) were detected by real time PCR and gelatin zymography. The mRNA and protein expressions of E-cadherin, β-catenin, zonula occluden-1 (ZO-1), ZO-1-associated nucleic acid binding protein (ZONAB) and α-smooth muscle actin (α-SMA) were analyzed by real time PCR, Western blotting and immunocytochemistry. Results Compared with those in normal control group, in siRNA group the mRNA expressions of E-cadherin, β-catenin and ZO-1 decreased, and MMP9, MMP2, α-SMA and ZONAB increased after interfering NPHP124 h (all P<0.05); the protein expressions of E-cadherin,β-catenin and ZO-1 decreased and ZONAB and α-SMA increased after 48 h (all P<0.05), and MDCK cells became elongated with enhanced migration capacity; siRNA cells had decreased expressions of E-cadherin and β-catenin on the membrane, but increased expression of ZONAB in cytoplasm and nucleoplasm after 72 h, and α-SMA was also observed in some interfered cells. Conclusions NPHP1 knockdown induces epithelial-mesenchymal transition in MDCK cells, and ZO-1/ZONAB signaling pathway was activated. These changes may associate with renal interstitial fibrosis of Nephronophthisis type I.

Nephronophthisis

NPHP is the most common monogenic cause of CKD in children or adolescents. Extra-renal symptoms often accompany, therefore examination of retina, hearing, and skeleton is necessary in patients with CKD with insidious onset. Genes involved in NPHP-RC are mostly related in primary cilia. While genetic diagnosis is necessary for definitive diagnosis, there is no curative treatment.

Nephronophthisis

NPHP is the most common monogenic cause of CKD in children or adolescents. Extra-renal symptoms often accompany, therefore examination of retina, hearing, and skeleton is necessary in patients with CKD with insidious onset. Genes involved in NPHP-RC are mostly related in primary cilia. While genetic diagnosis is necessary for definitive diagnosis, there is no curative treatment.

Two Cases of Senior-Loken Syndrome in Siblings

Although juvenile nephronophthisis(NPHP) is one of the most frequent genetic causes of chronic renal failure, it has very rarely been reported in Korean children. Most NPHP patients are found to have chronic renal failure, since there are no distinct clinical symptoms for NPHP except polydipsia, polyuria and enuresis in the early stage of disease. Ten percent of NPHP patients manifest retinitis pigmentosa, called Senior-Loken syndrome. We experienced 2 cases of Senior-Loken syndrome that occurred in siblings(a 10 year-old boy and a 14-year-old girl) who were diagnosed with Leber's amaurosis. They were found to have severe renal impairment without polydipsia and polyuria. However, no large homogenous deletion of the NPHP1(2q13) gene was not identified in these patients. We report here on these cases and we review the literature to emphasize the association between Leber's amaurosis and the development of chronic renal failure.

A Case of Medullary Cystic Disease which Progressed to End Stage Renal Disease during Pregnancy / 대한신장학회잡지

Medullary cystic disease (MCD) and familial juvenile nephronophthisis are inherited diseases characterized by development of small cysts at the cortico- medullary borders of the kidneys. Both diseases consist of microscopic or gross cysts of the renal medullae associated with atrophy of nephrons, anemia, renal insufficiency, polyuria, and salt-wasting. We report a 27-year-old pregnant female patient with MCD which caused acute renal failure progressing to end stage renal disease during the second trimester. Hypertension, oliguria, preeclampsia, placenta abruptio, and disseminated intravascular coagulation were also accompanied. Radiologically, abdominal ultrasonography and computed tomogram showed many cysts confined only to the renal medullae, which are typical findings consistent with MCD. In spite of conservative therapy, her renal function deteriorated rapidly and uremic symptoms including pulmonary edema were aggravated. She was started on hemodialysis and she has received regular hemodialysis without recovery of renal function.