[Genetic variants of familial hematuria associated genes in three families with hematuria with probands initially diagnosed as IgA nephropathy].

ABSTRACT

Objective: To examine genetic variants of familial hematuria (FH) associated genes in 3 families with hematuria with probands initially diagnosed with IgA nephropathy (IgAN). Methods: A retrospective analysis was performed on the clinical data, laboratory tests and genetic test results of three children with hematuria and the probands in three families with hematuria. The families were ascertained at the Department of Pediatrics, Fuzhou General Hospital of Nanjing Military Command from August 2014 to May 2018. Results: The proband of Family One, an 8-year-old boy, manifested gross hematuria. His renal biopsy pathology revealed IgAN. His father also manifested hematuria. Genetic testing showed that the proband and his father carried a heterozygous variant of the CFHR5 gene,533A>G (Asn178Ser). The child of Family Two, a 4-year-old girl, manifested hematuria. Her father, the proband of the family, was 36 years old, and manifested hematuria, proteinuria, high-frequency sensorineural deafness and renal insufficiency. He was diagnosed as IgAN according to clinical manifestations, renal pathology and routine immunohistochemistry without renal biopsy electron microscopy, renal tissue type Ⅳ collagen α3, α4, α5 chains immunofluorescence and skin type Ⅳ collagen α5 chain immunofluorescence. Genetic testing showed that the girl carried a heterozygous variant of the COL4A5 gene,566G>T (Gly189Val), and her father carried the hemizygous variant. The child of Family Three, a 7-year-old girl, manifested hematuria and proteinuria. Her mother, the proband of the family, was 34 years old, and manifested hematuria and proteinuria as well. The proband was diagnosed as IgAN by the same method used for Family Two. The girl's grandfather died of uremia at the age of 44. Genetic testing showed that the girl and her mother carried a heterozygous variant 539G>A (Gly180Glu)in COL4A5 gene. Conclusions: The variant of the CFHR5 gene identified in Family One is of uncertain signifance, and the two variants of the COL4A5 gene identified in Families Two and Three are pathogenic. The probands of Families Two and Three are diagnosed as Alport syndrome. The study suggests that clinicians should examine genetic variants of FH associated genes in families with hematuria when the probands were diagnosed as IgAN by their clinical manifestations, renal pathology and routine immunohistochemistry.