Genetic analysis of COL4A4 gene in familial hematuria / 中华肾脏病杂志

ABSTRACT

Objective:To define more information for familial hematuria by genetic screening in a pedigree with familial hematuria.Methods:This was a 4 generation pedigree included 20 family members. The clinical data and laboratory manifestations of the family members were reviewed and collected from medical records. Meanwhile, the peripheral blood samples of 11 family members of the pedigree were collected, and then DNA samples were extracted by salting out method for genetic analysis. For genetic analysis, firstly, three family members including the proband were selected for whole exome sequencing, and the genetic variations were screened according to the sequence variation interpretation guidelines from the American College of Medical Genetics and Genomics (ACMG) for diagnostic sequence interpretation. Then PCR and Sanger sequencing were used to verify the identified pathogenic variants in all family members in the pedigree.Results:In the pedigree, 6 female members had persistent hematuria. Among them, 2 died due to end-stage renal disease, 2 died due to non-renal diseases, and 2 maintained stable renal function. One of the two members with stable renal function was diagnosed as IgA nephropathy by renal biopsy. Moreover, diffuse basement membrane lesions were identified in her renal biopsy sample after the electron microscope examination, which resulted in the suspected diagnosis of Alport syndrome. Genetic testing in this pedigree revealed two novel mutations in COL4A4 gene (NM_000092), c.G446Tp.G149V in exon 7 and c.G1249Ap.G417R in exon 20. Conclusion:Two novel mutations of COL4A4 gene (c.G446Tp.G149V in exon 7 and c.G1249Ap.G417R in exon 20) in a hematuria pedigree are related with phenotype of familial hematuria.