Diagnosis; Screening

Patients with low levels of red blood cell plasmalogens are associated with defects in peroxisomal plasmalogen synthesis; confirmed by testing plasmalogen synthesis enzymes in cultured skin fibroblasts and mutation analyses in one of the three genes associated with RCDP and one of the more than 16 genes associated with the … Patients with low levels of red blood cell plasmalogens are associated with defects in peroxisomal plasmalogen synthesis; confirmed by testing plasmalogen synthesis enzymes in cultured skin fibroblasts and mutation analyses in one of the three genes associated with RCDP and one of the more than 16 genes associated with the Zellweger spectrum disorders. View more

Establish or confirm diagnosis

rhizomelic chondrodysplasia punctata

Sample Negative Report Help
Sample Negative Report

Sample Positive Report Help
Sample Positive Report

Preparation of washed red blood cells from whole EDTA blood. Extraction of red blood cells with hexane:isopropanol, centrifuge, dry the solvent layer, add 1.0N methanolic HCL, incubate at 75 deg C. for 2 hours, extract dimethylacetals with hexane , inject on 50meter DB-1 capillary column and measure 16:0, 18:0 and … Preparation of washed red blood cells from whole EDTA blood. Extraction of red blood cells with hexane:isopropanol, centrifuge, dry the solvent layer, add 1.0N methanolic HCL, incubate at 75 deg C. for 2 hours, extract dimethylacetals with hexane , inject on 50meter DB-1 capillary column and measure 16:0, 18:0 and 18:1 dimethylacetals by flame ionization detection. View more

All abnormal tests are confirmed by retesting a new aliquot of the original sample using two different capillary columns differing in polarity.

In order to define the type of rhizomelic chondrodysplasia puncatata, biochemical testing of plasmalogen synthesis enzymes assays and phytanic acid oxidase are performed using cultured skin fibroblasts.

Tests performed
Entire test performed in-house

More than 100 control speciimens were tested to determine the range of normal; more than 25 samples from patients known to have peroxisomal plasmalogen synthesis defects were tested to determine the abnormal range. The same normal red blood cell control ( from Red Cross) and abnormal red blood cell ( … More than 100 control speciimens were tested to determine the range of normal; more than 25 samples from patients known to have peroxisomal plasmalogen synthesis defects were tested to determine the abnormal range. The same normal red blood cell control ( from Red Cross) and abnormal red blood cell ( from dog blood) are assayed with each batch of samples. For the set of analyses to be valid the normal and abnormal must fall within the specified range (trend analysis). View more

Red blood cells prepared outside of our laboratory may not be washed and/or stored properly and may give falsely low levels of plasmalogens.

Is proficiency testing performed for this test? Help
Yes

Method used for proficiency testing: Help
Inter-Laboratory

PT Provider: Help
Biochemical Genetics Laboartory in Amsterdam

Description of PT method: Help
sample exchange

Description of internal test validation method: Help
The same normal red blood cell control ( from Red Cross) and abnormal red blood cell ( from dog blood) are assayed with each batch of samples. For the set of analyses to be valid the normal and abnormal must fall within the specified range (trend analysis).

Software used to interpret novel variations Help
proprietary internal software

Laboratory's policy on reporting novel variations Help
call referring laboratory/physician and fax report, requesting a new sample