Aberrant Splicing of COL4A5 Intronic Variant Contribute to the Pathogenesis of X-Linked Alport Syndrome: A Case Series

Figures & data

Figure 1 Sequence analysis of the pedigree and in vitro splicing experiments (a) pedigree of the Chinese family with XLAS. Black filled symbols represent affected individuals; The symbols with a slash correspond to deceased individuals; Arrow indicates the proband; M represent mutation (c.321+5G>A), N represent normal, / indicate not detect. (b) Sanger sequencing of the proband and his parents. (c) Electrophoresis for amplification of COL4A5 cDNA from the skin tissue of healthy individual and proband. (d) Schematic overview of the region harboring c.321+5G>A mutation in COL4A5 and representation of the abnormal splicing. Representation of the alternative splicing of exon 5 in COL4A5. (e) Sequencing chromatogram of COL4A5 wild-type cDNA and splice variants.

Table 1 Clinical Data of Patients with the COL4A5 Gene Variant

No.	Sex	Age (year)	Age Of Onset (year)	Hematuria	Proteinuria	Stage Of CKD	Age Of Onset CKD (year)	Ultrasound	Renal Function
IV-7	Male	22	11	+++	+++	V	17	Enhanced echogenicity of both renal parenchyma with indistinct corticomedullary demarcation	Abnormal
III-8	Female	48	34	+	+++	V	43	Enhanced echogenicity and decreased blood flow in both renal parenchyma	Abnormal
IV-2	Female	23	20	+	++	III	20	Enhanced echogenicity of both renal parenchyma with indistinct corticomedullary demarcation; echogenic enhancement of the left renal calyx margin	Abnormal
IV-5	Female	24	17	+++	-	I	17	Enhanced echoes of the calyx margins of both kidneys; calcification	Normal
IV-6	Male	15	15	+++	++	I	16	Enhanced echoes of the calyx margins of both kidneys; calcification	Normal
IV-9	Male	34	21	+	+++	V	28	Macular dense shadows in the medulla of the left kidney clustered around the calyx	Normal
IV-17	Female	28	16	+++	+	I	17	Few punctate strong echoes at the cortico-medulla junction	NA
III-1	Female	43	31	++	+++	III	43	NA	Abnormal
III-13	Female	55	54	+	+	I	54	NA	NA

Abbreviations: NA, not available; “-”, negative; “+”, minor; “++”, moderate; “+++”, massive.

Figure 2 Electron microscopy images of his kidney of IV-6 (A-C) show two glomeruli under electron microscopy. Electron microscopy of renal showed glomerular capillary endothelial cells, renal tubular epithelial cells, and visceral epithelial cells with vacuolar degeneration; segmental fusion of foot processes; irregular with an uneven density of glomerular basement membrane thickness. The black arrow indicates an abnormally thick basement membrane.