Inherited platelet disorders (IPD) are a heterogeneous group of rare bleeding diseases associated with a reduction of platelet number and/or function and with a bleeding tendency ranging from mild to severe. The frequency of inherited thrombocytopenias has been estimated to be 2.7/100,000 while the prevalence of inherited platelet function disorders is unknown, partly because they are frequently overlooked due to their difficult diagnosis.

This a no-profit national multicenter ambispectic (retrospective and prospective) observational study.

After collection of informed consent form each patient, each center will enroll the patient and will collect general, laboratory and clinical data on an electronic CRF on a REDCAP platform. Each patient will receive a unique identification number. All clinical events will be reported in the data base.

Inclusion Criteria:

• All patients with established diagnosis of inherited number or function platelet disorder (IPN and IPD, respectively), on the basis of internationally established clinical, laboratory and genetic criteria will be enrolled.
• For patients <18 ys, consensus will be signed by parents or legal responsible

Exclusion Criteria:

• No written consent
• Undocumented or uncertain diagnosis

All patients with established diagnosis of inherited number or function platelet disorder (IPN and IPD, respectively), on the basis of internationally established clinical, laboratory and genetic criteria will be enrolled.