• Turnaround time:
    10–21 calendar days (14 days on average)
  • Preferred specimen:
    3mL whole blood in a purple-top tube
  • Alternate specimens:
    DNA or saliva/assisted saliva
  • Sample requirements
  • Request a sample kit



1; SAMWD1; SPG54; gamma; iPLA

Associated disorders

The DDHD2 gene is associated with autosomal recessive hereditary spastic paraplegia 54 (SPG54) (MedGen UID: 761341).

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Invitae tests that include this gene:

DDHD2 is a rare cause of hereditary spastic paraplegia overall; an estimated 2% of autosomal recessive hereditary spastic paraplegia is caused by pathogenic variants identified in DDHD2.

DDHD2 encodes the DDHD domain-containing protein 2, a phospholipase that has been shown to metabolize phosphatidic acid, a signaling molecule involved in many pathways. DDHD2 has been reported to function in membrane trafficking between the Golgi apparatus and the plasma membrane and is expressed in the brain.

Assay and technical information

Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).

Our sequence analysis covers clinically important regions of each gene, including coding exons, +/- 10 base pairs of adjacent intronic sequence in the transcript listed below. In addition, analysis covers the select non-coding variants specifically defined in the table below. Any variants that fall outside these regions are not analyzed. Any specific limitations in the analysis of these genes are also listed in the table below.

Our analysis detects most intragenic deletions and duplications at single exon resolution. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. If you are requesting the detection of a specific single-exon copy number variation, please contact Client Services before placing your order.

Gene Transcript reference Sequencing analysis Deletion/Duplication analysis
DDHD2 NM_015214.2