title: Mutations in TTC21B cause different phenotypes in two childhood cases in China.
abstract: OBJECTIVE
  The TTC21B gene is now known as causative of nephronophthisis-related ciliopathies (NPHP-RC). We reported two Chinese paediatric cases with end-stage renal disease and other phenotypes caused by the TTC21B gene mutations.
  
  
  METHODS
  The clinical features of Chinese paediatric cases with NPHP-RC were summarized. Mutation analysis of the TTC21B gene was performed using next-generation sequencing.
  
  
  RESULTS
  The two cases both had nephrotic proteinuria, renal failure, hypertension and abnormal liver function (or hepatic fibrosis). One case also presented situs inversus and short phalanges. They developed end-stage renal disease (ESRD) at 1 year old and 8 years old, respectively, when renal pathology both showed focal segmental glomerular sclerosis (FSGS) with tubulointerstitial lesions including interstitial fibrosis and atrophic tubules. Three novel disease-causing TTC21B mutations were identified. One case carried homozygous mutation c.2211 + 3A > G, while the other case carried compound heterozygous mutations c.1552 T > C (p.C518R) and c.1456dupA (p.R486KfsX22).
  
  
  CONCLUSIONS
  Mutations in TTC21B cause a range of ciliopathy phenotypes in humans. We identified 3 novel TTC21B mutations in two Chinese paediatric cases that both presented end-stage renal disease and other different features. This is the first TTC21B mutations ever reported in China.
authors.affiliation: Department of Pediatric, Peking University First Hospital, Beijing, China.
authors.forename: Hongwen
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Pediatric, Peking University First Hospital, Beijing, China.
authors.forename: Baige
authors.initials: B
authors.lastname: Su
authors.affiliation: Department of Pediatric, Peking University First Hospital, Beijing, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Pediatric, Peking University First Hospital, Beijing, China.
authors.forename: Huijie
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Department of Pediatric, Peking University First Hospital, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ding
authors.affiliation: Department of Pediatric, Peking University First Hospital, Beijing, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yao
mesh_terms: D002648:Child; D002681:China; D000072661:Ciliopathies / Q000150:complications / Q000175:diagnosis / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods; D018450:Disease Progression; D017809:Fatal Outcome; D005260:Female; D020022:Genetic Predisposition to Disease; D005923:Glomerulosclerosis, Focal Segmental / Q000209:etiology; D006579:Heterozygote; D059014:High-Throughput Nucleotide Sequencing; D006720:Homozygote; D006801:Humans; D007223:Infant; D052177:Kidney Diseases, Cystic / Q000150:complications / Q000175:diagnosis / Q000235:genetics*; D007676:Kidney Failure, Chronic / Q000209:etiology; D008297:Male; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D013997:Time Factors
chemical_list: D008869:Microtubule-Associated Proteins; C000594121:TTC21B protein, human
keywords: 
  TTC21B
  ; ciliopathies; end-stage renal disease; nephronophthisis