Table 3.
Clinical and laboratory features of hereditary TTP and hemolytic uremic syndrome.
| Disorder | Hereditary TTP | Hereditary atypical HUS | ||
|---|---|---|---|---|
| Gene affected | ADAMTS13 | CFH | IF | MCP |
| No. of cases | > 60 | > 50 | 4 | 13 |
| Location of mutations | Entire ADAMTS13 gene | CCPR18-20: 63% | Trypsin domain | CCPR4 |
| Inheritance | Recessive | Dominant with variable penetrance | ||
| Age affected, yrs | Newborn – adult | Newborn – adult | Newborn – adult | Child – adult |
| Neurological complications | Common | Uncommon | Uncommon | Uncommon |
| Hypertension | Rare | Common | Common | Common |
| Acute renal failure | Occasional | Yes | Yes | Yes |
| Chronic renal failure | Uncommon | Common | Common | Common |
| Diagnosis | ADAMTS13 < 10% Parents: partial deficiency Genetic study | Factor H assay Genetic study | Factor I assay Genetic study | MCP assay Genetic study |
| Plasma infusion | Effective (every 2–3 weeks) | Probably effective, ?optimal regimen | Probably ineffective | |
| Relapse after renal transplant | Renal transplant not needed | Yes | Yes | No (0 of 3 cases) |
| Animal model | Yes | Yes (MPGN) | No | No |
CCPR: complement control protein repeat; CFH: complement factor H; HUS: hemolytic uremic syndrome; IF: complement factor I; MCP: membrane co-factor protein; MPGN: membranoproliferative glomerulonephropathy; TTPL thrombotic thrombocytopenic purpura.