TTP constitutes a classic pentad of fever, microangiopathic haemolysis, thrombocytopenia, renal impairment and neurological disturbance.
Clinical severity is variable. Some patients present with the disease neonatally, whereas others have an adult onset that can be triggered by pregnancy. Some patients may experience only a few isolated episodes of TTP, whereas others have frequent recurrences.
Acquired deficiency of ADAMTS13 is much more common than the inherited disorder, with only about 5-10% of cases being inherited.
Indications for Testing
Diagnostic testing to confirm or exclude a clinical diagnosis of inherited ADAMTS13 deficiency.
Testing in relatives of an affected individual for clinical management and genetic counselling. These referrals require that the recessively inherited pathogenic mutation(s) have been identified in the index case.
Sequencing of the protein-coding region is expected to detect >90% of disease alleles in individuals with an inherited deficiency.
Venous blood (2-5ml K-EDTA, not to be frozen prior to or during transport)
Genomic DNA (approximately 5μg)
Specimen containers and referral forms must be labelled with at least two corresponding unique identifiers.
Approximately 8 weeks (40 working days) from receipt of sample. A priority service may be available for urgent referrals at an additional cost, please contact the laboratory for further information.
Referrals must generally be made from the Clinical Genetics services or appropriate clinical specialist. It is assumed that informed consent for genetic testing has been obtained from the patient or their parent/guardian and that the implications of a positive result for other family members have been discussed.
NGS of ADAMTS13 exons 1-29 (entire coding region)
Congenital Thrombotic Thrombocytopenic Purpura Diagnostic Test