Refsum Disease - Diagnostic Tests

Diagnostic Tests

The diagnosis of RD relies on the demonstration of elevated plasma phytanic acid levels, which can be increased up to 100-fold (normal levels are below 33 microM).

Urine levels of phytanic acid are also increased.

Skin biopsy shows lipid vacuoles in the basal and suprabasal epidermal cells

Fibroblast culture shows decreased phytanic acid oxidase acitivity.

In patients with disease due to mutations in PEX7, erythrocyte plasmalogen levels and dihydrooxyacetone phosphate acyltransferase (DHAP) activity in platelets and fibroblasts are reduced.

Diagnostic Tools

This section offers to professional users instruments helpful to establish the disease diagnosis. Specific entries include:

  1. model questionnaires, protocols, or checklists, which may guide clinicians and laboratory personnel in the diagnostic procedure of specific disease groups/subgroups;
  2. a list of cell biology/biochemical tools used for laboratory diagnosis of specific diseases or group of diseases;
  3. a list of molecular genetics tools, including mutational screening procedures, oligonucleotide primer sequences, PCR amplification conditions, and other details for selected diseases. In this section, you also find the link for the gene-specific page of the Weizmann Institute of Science GeneCards website ( which is an integrated database including information on disease relationships, SNPs, gene expression, gene function and more.
  4. a mutation database with a GENESKIN updated list of the mutations identified in the genes responsible for selected diseases. A link with the gene-specific page at the Human Gene Mutation Database maintained at the University of Wales in Cardiff ( and other databases, such as the collagen database in Leicester (, is also available.

Molecular Genetic Tools

Causative genes

PHYH Genecards Logo
PEX7 Genecards Logo

Mutation Database

Causative genes