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Aim: The TTC21B gene is now known as causative of nephronophthisisrelated 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 nextgeneration sequencing. Results: The twocases 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 diseasecausing TTC21B mutations were identified. One case carried homozygous mutation c.2211 +3A>G,while the other case carried compoundheterozygous mutations c.1552 T > C (p.C518R) and c.1456dupA (p.R486KfsX22). Conclusion: 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. [ABSTRACT FROM AUTHOR]

Alport syndrome (AS) is a progressive renal disease characterized by haematuria and progressive renal failure. An accurate genetic diagnosis of AS is very important for genetic counselling and even prenatal diagnosis. We detected mutation of COL4An by amplifying the entire coding sequence mRNA of peripheral blood lymphocytes using polymerase chain reaction (PCR) in five Chinese AS families who asked for genetic counselling and prenatal diagnosis, then performed prenatal genetic diagnosis for four families. Mutation analysis of the foetus was made using DNA extracted from amniocytes. Foetus sex was determined by PCR amplification of SRY as well as karyotype analysis. Maternal cell contamination was excluded by linkage analysis. Four different COL4A5 gene variants and two COL4A3 gene variants were detected in the five families. Because there was a de novo mutation in family 2, prenatal diagnosis was performed for the other four families. Results showed a normal male foetus for family 1 and family 4, respectively. Results showed an affected male foetus for families 3 and 5, and the pregnancies were terminated. An easier, faster and efficacious method for COL4An gene mutation screening based on mRNA analysis from peripheral blood lymphocytes was established. Prenatal genetic diagnosis was performed in four AS families in China. Prenatal genetic diagnosis was performed in Alport syndrome families in China. A rapid and efficacious method for screening of the COL4An gene mutation for Alport syndrome is presented, based on mRNA analysis from peripheral blood lymphocytes. [ABSTRACT FROM AUTHOR]