Table 1.
Number and proportion of 300 families with steroid-resistant nephrotic syndrome, in whom causative mutations in one of 23 known monogenic causes of steroid-resistant nephrotic syndrome were detected
| Gene | Number of Families with Causative Mutation | Percentage of Families with Gene, % | Number of Mutations Known from Biobasea | Number of Novel Mutations |
|---|---|---|---|---|
| SRNS genes | ||||
| NPHS1 | 13 | 18 | 10 | 1 |
| PLCE1 | 11 | 15 | 8 | 2 |
| NPHS2 | 8 | 11 | 9 | 1 |
| SMARCAL1 | 8 | 11 | 5 | 1 |
| LAMB2 | 6 | 8 | 3 | 3 |
| NUP93 | 4 | 5 | 2 | 1 |
| MYO1E | 2 | 3 | 1 | 1 |
| SGPL1 | 3 | 4 | — | 2 |
| WDR73 | 3 | 4 | 3 | — |
| ITGA3 | 2 | 3 | 2 | — |
| LMX1B | 2 | 3 | 1 | — |
| NUP205 | 2 | 3 | 2 | — |
| TTC21B | 2 | 3 | 1 | 1 |
| WT1 | 2 | 3 | 1 | — |
| COQ2 | 1 | 1 | 1 | 1 |
| DGKE | 1 | 1 | 1 | — |
| INF2 | 1 | 1 | — | 1 |
| KANK4 | 1 | 1 | 1 | — |
| PDSS2 | 1 | 1 | 1 | — |
| TRPC6 | 1 | 1 | 1 | — |
| Total | 74 | 100 | 53 | 15 |
| Phenocopy genes | ||||
| COL4A5 | 3 | 27 | 2 | — |
| AGXT | 2 | 18 | 0 | 2 |
| CLCN5 | 1 | 9.1 | — | 1 |
| COL4A3 | 1 | 9.1 | — | 1 |
| CTNS | 1 | 9.1 | 1 | — |
| FN1 | 1 | 9.1 | — | 1 |
| GLA | 1 | 9.1 | 1 | — |
| WDR19 | 1 | 9.1 | 1 | — |
| Total | 11 | 100.0 | 5 | 5 |
Fifty-three of the mutations detected have previously been reported in BioBase, and 15 are novel (respective genes are under the table subheading ‘SRNS genes’). The most common genes to have a mutation detected in steroid-resistant nephrotic syndrome families were NPHS1, PLCE1, NPHS2, and SMARCAL1 (51% of all steroid-resistant nephrotic syndrome gene mutations detected). In an additional 11 families, mutations were detected in eight genes that cause a kidney disease that is a phenocopy of steroid-resistant nephrotic syndrome (respective genes are under the table subheading ‘Phenocopy genes’). Five of the mutations identified have previously been reported in BioBase, and five are novel. SRNS, steroid-resistant nephrotic syndrome; —, no mutations detected.