Scientists from the Broad Institute, Cambridge, Massachusetts identified the genetic cause of UKD as mutations in the MUC1 gene.

Medullary cystic kidney disease type 2 is due to mutations in a gene named "UMOD" on chromosome 16 that encodes a protein called uromodulin This disease is also autosomal dominant, meaning that it is characterized by a 50% chance of inheritance and slowly progressive chronic kidney disease that leads to the need for dialysis or a kidney transplant. Individuals and families with this disease suffer from gout relatively early in life. Individuals with a mutation in this gene can have a variable rate of loss of kidney function.

In MKD2 inheritance, just as MKD1, "autosomal dominant" indicates that 50% of children of an affected individual will inherit the disease. ""Tubulointerstitial"" is used because the problems that occur in this disease happen in the compartment of the kidney known as the tubulo-interstitium, a shorter name of the disease is used by most individuals- uromodulin kidney disease (UKD).

Current medical treatments result in survival of some longer than 10 years; in part this is because better diagnostic testing means early diagnosis and treatments. Older diagnosis and treatments resulted in published reports of median survival of approximately 5 years from time of diagnosis. Currently, median survival is 6.5 years. In rare instances, WM progresses to multiple myeloma.

The International Prognostic Scoring System for Waldenström’s Macroglobulinemia (IPSSWM) is a predictive model to characterise long-term outcomes. According to the model, factors predicting reduced survival are:

- Age > 65 years

- Hemoglobin ≤ 11.5 g/dL

- Platelet count ≤ 100×10/L

- B2-microglobulin > 3 mg/L

- Serum monoclonal protein concentration > 70 g/L

The risk categories are:

- Low: ≤ 1 adverse variable except age

- Intermediate: 2 adverse characteristics or age > 65 years

- High: > 2 adverse characteristics

Five-year survival rates for these categories are 87%, 68% and 36%, respectively. The corresponding median survival rates are 12, 8, and 3.5 years.

The IPSSWM has been shown to be reliable. It is also applicable to patients on a rituximab-based treatment regimen. An additional predictive factor is elevated serum lactate dehydrogenase (LDH).

Waldenström's macroglobulinemia is characterized by an uncontrolled clonal proliferation of terminally differentiated B lymphocytes. The most commonly associated mutations, based on whole-genome sequencing of 30 patients, are a somatic mutation in MYD88 (90% of patients) and a somatic mutation in CXCR4 (27% of patients). An association has been demonstrated with the locus 6p21.3 on chromosome 6. There is a two- to threefold increased risk of WM in people with a personal history of autoimmune diseases with autoantibodies, and a particularly elevated risk associated with liver inflammation, human immunodeficiency virus, and rickettsiosis.

There are genetic factors, with first-degree relatives of WM patients shown to have a highly increased risk of also developing the disease. There is also evidence to suggest that environmental factors, including exposure to farming, pesticides, wood dust, and organic solvents, may influence the development of WM.