The primary objective of this study is to establish the natural history of Farber disease (acid ceramidase deficiency) through the collection and analysis of retrospective and prospective data on patients diagnosed with Farber disease. All patients diagnosed with Farber disease are eligible, including both those who have and have not undergone hematopoietic stem cell transplantation (HSCT). Additionally, data and records from deceased patients will provide valuable retrospective data for this study.

The secondary objective of the study is to establish a set of clinical data, laboratory data (biomarkers), and functional data potentially useful for:

• Assessing the efficacy of HSCT and the efficacy of potential future therapies (for example with RVT-801, recombinant human acid ceramidase) in Farber disease
• Characterizing changes in symptoms of patients over time
• Characterizing distinct groups (phenotypes) within the patient population
• Documenting the disease histories of individual patients to serve as intra-subject control data for those who may enroll in any future clinical studies with therapies for Farber disease

The exploratory objectives of the study are:

• To explore the relationship between patient disease activity or phenotype and specific ceramide levels or specific immunologic markers (cytokines/chemokines) in blood
• To evaluate a standardized tool, the Farber Disease Natural History Instrument (FDNI), to be used for the collection of patient history information, data from clinical, laboratory, genetic, and functional studies, and data from review of medical records

Inclusion Criteria:

• Living or deceased subjects with diagnosis of Farber disease, based on clinical (typical clinical symptoms) and biochemical and/or genetic criteria, as follows:

  • Biochemical: An acid ceramidase activity value in white blood cells, cultured skin fibroblasts or other biological sources (e.g., plasma) that is less than 30% of control (normal) values established by the testing laboratory. For deceased subjects only, storage of ceramide in cells from histopathologic sections is also adequate to confirm the diagnosis.
  • Genetic: Nucleotide changes within both alleles of the acid ceramidase gene (ASAH1) or cDNA that indicate, through bioinformatics, gene expression studies, or other methods, a possible loss of function of the acid ceramidase protein.

• Informed consent or assent, for living subjects. For deceased subjects it is the responsibility of the principal investigator to ensure that the proper requirements are met according to local laws and regulations.

Exclusion Criteria:

• Current use or history of use in the past 30 days of an investigational agent (with exception of off-label use of medications).

All identified patients with Farber disease, living or deceased, diagnosed by biochemical or genetic criteria, or both, are eligible for inclusion in the study without regard to any other baseline or demographic characteristics. Both subjects who have undergone HSCT and those who have not are eligible to participate.