OBJECTIVE: To explore the clinical characteristics and genetic basis of two Chinese pedigrees affected with Joubert syndrome. METHODS: Clinical data of the two pedigrees was collected. Genomic DNA was extracted from peripheral blood samples and subjected to high-throughput sequencing. Candidate variants were verified by Sanger sequencing. Prenatal diagnosis was carried out for a high-risk fetus from pedigree 2. RESULTS: The proband of pedigree 1 was a fetus at 23⁺⁵ weeks gestation, for which both ultrasound and MRI showed "cerebellar vermis malformation" and "molar tooth sign". No apparent abnormality was noted in the fetus after elected abortion. The fetus was found to harbor c.812+3G>T and c.1828G>C compound heterozygous variants of the INPP5E gene, which have been associated with Joubert syndrome type 1. The proband from pedigree 2 had growth retardation, mental deficiency, peculiar facial features, low muscle tone and postaxial polydactyly of right foot. MRI also revealed "cerebellar dysplasia" and "molar tooth sign". The proband was found to harbor c.485C>G and c.1878+1G>A compound heterozygous variants of the ARMC9 gene, which have been associated with Joubert syndrome type 30. Prenatal diagnosis found that the fetus only carried the c.485C>G variant. A healthy infant was born, and no anomalies was found during the follow-up. CONCLUSION The compound heterozygous variants of the INPP5E and ARMC9 genes probably underlay the disease in the two pedigrees. Above finding has expanded the spectrum of pathogenic variants underlying Joubert syndrome and provided a basis for genetic counseling and prenatal diagnosis.
Female ; Humans ; Pregnancy ; Pedigree ; Cerebellum/abnormalities* ; Abnormalities, Multiple/diagnosis* ; Eye Abnormalities/diagnosis* ; Kidney Diseases, Cystic/diagnosis* ; Phosphoric Monoester Hydrolases/genetics* ; Retina/abnormalities* ; East Asian People ; Mutation

OBJECTIVES: To study the clinical and genetic features of Joubert syndrome (JS) in children. METHODS: A retrospective analysis was performed on the clinical data, genetic data, and follow-up data of 20 children who were diagnosed with JS in the Department of Children's Rehabilitation, the Third Affiliated Hospital of Zhengzhou University, from January 2017 to July 2022. RESULTS: Among the 20 children with JS, there were 11 boys and 9 girls. The common clinical manifestations were developmental delay (20 children, 100%), abnormal eye movement (19 children, 95%), and hypotonia (16 children, 80%), followed by abnormal respiratory rhythm in 5 children (25%) and unusual facies (including prominent forehead, low-set ears, and triangular mouth) in 3 children (15%), and no limb deformity was observed. All 20 children (100%) had the typical "molar tooth sign" and "midline cleft syndrome" on head images, and 6 children (30%) had abnormal eye examination results. Genetic testing was performed on 7 children and revealed 6 pathogenic genes, i.e., the CPLANE1, RPGRIP1L, MKS1, CC2D2A, CEP120, and AHI1 genes. CONCLUSIONS For children with developmental delay, especially those with abnormal eye movement and hypotonia, it is recommended to perform a head imaging examination to determine the presence or absence of "molar tooth sign" and "midline cleft syndrome", so as to screen for JS to avoid missed diagnosis and misdiagnosis. There are many pathogenic genes for JS, and whole-exome sequencing can assist in the diagnosis of JS.
Male ; Female ; Humans ; Child ; Cerebellum ; Abnormalities, Multiple/genetics* ; Kidney Diseases, Cystic/genetics* ; Eye Abnormalities/genetics* ; Retina ; Retrospective Studies ; Muscle Hypotonia/genetics*

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.
Child ; Humans ; Retrospective Studies ; Syndrome ; Kidney Diseases, Cystic/genetics* ; Mutation ; Phenotype

OBJECTIVE: To explore the clinical features and genomic abnorm ality of a fetus enlarged multicystic dysplastic kidneys with oligohydramnios caused by NPHP3 gene mutation. METHODS: The fetuse was found to have multicystic dysplastic kidneys with oligohydramnios upon ultrasonography during the second trimester. Following induced abortion, fetal tissue was collected for the extraction of DNA, chromosomal microarray analysis (CMA) and whole exome sequencing (WES). Sanger sequencing was used to verify the suspected variants in the family. RESULTS: Antenatal ultrasound examination at 19 weeks showed "polycystic" kidneys with Oligohydramnios. Delivery was by induced labour because of the critically low amniotic fluid volume. Testing of CMA was normal. WES showed a compound heterozygous mutation of c.1817G>A, p.W606X; c.432dupA, p.E145Rfs*18 mutations are novel mutations in this study. CONCLUSION The research may further expand the NPHP3 gene mutation spectrum. Enlarged multicystic dysplastic kidneys with oligohydramnios caused by NPHP3 gene mutation at least include one or two splice site mutation, frameshift mutation or nonsense mutation foetal poor prognosis.
Amniotic Fluid ; Female ; Humans ; Kidney Diseases, Cystic ; Multicystic Dysplastic Kidney/genetics* ; Mutation ; Oligohydramnios/genetics* ; Polycystic Kidney Diseases ; Pregnancy ; Ultrasonography, Prenatal

Objective: To analyze the clinical characteristics of 6 children with TTC21B-related nephronophthisis to provide reference for early clinical diagnosis. Methods: The general condition, clinical manifestations, laboratory tests and other clinical data of 6 children from 4 families diagnosed with nephronophthisis by genetic testing in Shanghai Children's Hospital from January 2015 to December 2020 were analyzed retrospectively. Results: A total of 6 children (3 males and 3 females) developed proteinuria and progressive renal dysfunction in early infancy. The onset age of proteinuria was 18 (6, 25) months. The age at the onset of renal impairment was 22 (10, 36) months. All 6 children progressed to end-stage renal disease (ESRD) within 10 (4, 65) months of onset. Five children had hypertension, 3 children with abnormal liver function, 2 children with visceral translocation and 1 child with growth retardation. The genetic results suggested that all children carried variations TTC21B gene p.C518R. Conclusions: Children with TTC21B gene p.C518R nephronophthisis had proteinuria and progressed to ESRD at the early stage of life. These nephronophthisis patients commonly presented with liver and renal dysfunction.
China ; Female ; Humans ; Kidney Diseases, Cystic/genetics* ; Kidney Failure, Chronic/genetics* ; Male ; Phenotype ; Proteinuria/genetics* ; Retrospective Studies

OBJECTIVE: To analyze the phenotype and genetic variant of a fetus with dysplasia of cerebellar vermis. METHODS: Gestational status and family history of the gravida was taken in combination with the imaging results of the fetus. Following elected abortion, fetal tissue and peripheral blood samples of the couple were collected for the extraction of genome DNA. Whole exome sequencing was carried out to screen potential variant associated with the phenotype of the proband. Specific PCR primers were designed to verify the results by Sanger sequencing. RESULTS: Prenatal ultrasound revealed that the fetal vermis cerebellum was poorly developed, which was similar to the previous pregnancy. Whole exome sequencing revealed that the fetus has carried compound heterozygous variants of the CPLANE1 gene, namely c.7978C>T and c.7169delT, which were respectively inherited from the husband and wife. CONCLUSION The c.7978C>T and c.7169delT compound heterozygous variants of the CPLANE1 gene probably underlay the dysplasia of cerebellar vermis in the fetus, which has provided a basis for genetic counseling and prenatal diagnosis.
Abnormalities, Multiple/genetics* ; Cerebellum/diagnostic imaging* ; Eye Abnormalities/genetics* ; Female ; Fetus ; Humans ; Kidney Diseases, Cystic ; Mutation ; Phenotype ; Pregnancy ; Retina/abnormalities*

OBJECTIVE: To explore the pathogenesis of two siblings (including a fetus) from a pedigree affected with Joubert syndrome. METHODS: Peripheral blood samples of the proband and his parents as well as amniotic fluid and abortion tissues of the fetus were collected. Part of the samples were used for the extraction of DNA, and whole exome sequencing (WES) was carried out to screen potential variants in the proband and his parents. Suspected variants were subjected to bioinformatics analysis with consideration of the clinical phenotype, and were verified by Sanger sequencing of the proband, fetus and their parents.The remainders were used for the extraction of RNA, and the mechanism of splicing variant was validated by reverse transcription-PCR (RT-PCR). RESULTS: WES showed that both patients have carried c.175C>T (p.R59X) and c.553+1G>A compound heterozygous variants of the TMEM237 gene. Among these, c.175C>T was a nonsense mutation inherited from the asymptomatic mother, while c.553+1G>A was an alternative splicing mutation inherited from the asymptomatic father. RT-PCR showed that this variant has resulted in aberrant splicing by exon skipping. CONCLUSION The compound heterozygous variants of the TMEM237 gene probably underlay the etiology of Joubert syndrome in this pedigree. Above finding has enriched the phenotype and variant spectrum of the TMEM237 gene, and facilitated genetic counseling and prenatal diagnosis for the family.
Abnormalities, Multiple/genetics* ; Cerebellum/abnormalities* ; Eye Abnormalities ; Female ; Genotype ; Humans ; Kidney Diseases, Cystic ; Mutation ; Pedigree ; Phenotype ; Pregnancy ; Retina/abnormalities*

OBJECTIVE: To identify pathogenic variants in two families with patients suspected for Joubert syndrome(UBST) by cerebellar vermis hypoplasia. METHODS: Clinical data and peripheral venous blood and skin tissue samples were collected for the extraction of genomic DNA. Potential variants were screened by using targeted capture and next generation sequencing. Suspected variants were validated by PCR and Sanger sequencing. The frequency of the variants in the population was calculated. Pathogenicity of the variants was predicted by following the guidelines of the American College of Medical Genetics and Genomics (ACMG). Prenatal diagnosis was provided to these families upon subsequent pregnancy. RESULTS: The proband of family 1 was found to harbor homozygous c.2072delT (p.F691S*fs19) frameshift variant of the AHI1 gene, which may cause premature termination of translation of the Abelson helper integration site 1 after the 691st amino acid. The proband of family 2 was found to harbor compound heterozygous variants of the CPLANE1 gene, namely c.7243dupA (p.T2415Nfs*7) and c.8001delG (p.K2667Nfs*31), which can respectively lead to premature termination of translation of ciliogenesis and planar polarity effector 1 after the 2145th and 2667th amino acids. All of the three variants were previously unreported, and were predicted to be pathogenic by bioinformatic analysis. CONCLUSION The AHI1 c.2072delT and CPLANE1 c.7243dupA and c.8001delG variants probably underlay JBTS3 in family 1 and JBTS17 in family 2, respectively. Based on above results, prenatal diagnosis may be offered to the affected families upon their subsequent pregnancies.
Abnormalities, Multiple ; diagnosis ; genetics ; Adaptor Proteins, Vesicular Transport ; genetics ; Cerebellum ; abnormalities ; Eye Abnormalities ; diagnosis ; genetics ; Female ; Genetic Testing ; Genetic Variation ; Humans ; Kidney Diseases, Cystic ; diagnosis ; genetics ; Membrane Proteins ; genetics ; Mutation ; Pregnancy ; Prenatal Diagnosis ; Retina ; abnormalities

OBJECTIVE: To explore the pathogenesis of two fetuses from one family affected with Joubert syndrome (JS). METHODS: Whole exome sequencing was employed to screen potential mutations in both fetuses. Suspected mutations were verified by Sanger sequencing. Impact of intronic mutations on DNA transcription was validated by cDNA analysis. RESULTS: Two novel TCTN1 mutations, c.342-8A>G and c.1494+1G>A, were identified in exons 2 and 12, respectively.cDNA analysis confirmed the pathogenic nature of both mutations with interference of normal splicing resulting in production of truncated proteins. CONCLUSION The genetic etiology of the family affected with JS has been identified.Above findings have enriched the mutation spectrum of TCTN1gene and facilitated understanding of the genotype-phenotype correlation of JS.
Abnormalities, Multiple ; diagnosis ; genetics ; Cerebellum ; abnormalities ; Eye Abnormalities ; diagnosis ; genetics ; Humans ; Kidney Diseases, Cystic ; diagnosis ; genetics ; Membrane Proteins ; genetics ; Mutation ; Pedigree ; Retina ; abnormalities ; Whole Exome Sequencing

Nephronophthisis (NPHP) is a group of autosomal recessive tubulointerstitial cystic kidney disorders. This article reports a case of NPHP type 12 caused by TTC21B mutations. The girl had an insidious onset, with moderate proteinuria, renal dysfunction, stage 2 hypertension, situs inversus, and short phalanges when she visited the hospital for the first time at the age of 3 years and 6 months. The renal lesions progressed to end-stage renal disease (ESRD) before she was 4 years old. Urine protein electrophoresis showed glomerular proteinuria. There were significant increases in urinary β2-microglobulin and α1-microglobulin. Gene detection revealed two compound heterozygous mutations, c.1552T>C (p.C518R) and c.752T>G (p.M251R), in the TTC21B gene, which came from her father and mother respectively. The c.752T>G mutation was a novel mutation. It is concluded that besides typical tubular changes of NPHP, marked glomerular damage is also observed in patients with TTC21B gene mutations.
Child, Preschool ; Female ; Genotype ; Humans ; Kidney ; Kidney Diseases, Cystic ; Kidney Failure, Chronic ; Microtubule-Associated Proteins ; genetics ; Mutation ; Nephrosis ; genetics