This study investigates families with at least two cases of B-cell lymphoproliferative disorders (LPD), and evaluates the prevalence of LPD in families, the relationship between medical history, genetic factors, and the risk of familial LPD, and various clinical outcomes for these families in a multiethnic population of Jews and Arabs in Israel.

Inclusion Criteria:

• Patient inclusion criteria:

Patients must have LPD and must have a family history of LPD. LPD patients who signed an informed consent to participate in the study.

Criteria for the inclusion of relatives of patients:

Relatives must be related by blood to LPD patients or unrelated (for control group).

Relatives who signed an informed consent to participate in the study.

Exclusion Criteria:

• Pregnant women, special populations and those lacking judgment will not be included

Jewish and Arab LPD families with at least 2 family members with LPD.