Characteristics of the test: (includes 1 gene)

SPG7, PGN (OMIM #602783)

Basic characteristics of the clinical phenotype:

Hereditary spastic paraplegia (HSP) is a group of clinically and genetically heterogeneous neurodegenerative diseases with major clinical features including progressive weakness and spasticity in the lower limbs, hyperreflexia, extensor-plantar response, and a characteristic spastic-paraparetic gait. The onset of the disease can vary from infancy to adulthood. It is due to loss of function of the pyramidal tracts due to axonal degeneration.

Mutations in the SPG7 (PGN) gene are associated with later onset, but can vary between 10-42 years and spastic-ataxic gait. Clinically, it can be represented by a pure or complex form of the disease, which in most patients includes reduced vibration sensation and cerebellar symptoms. Additional symptoms can also be observed: urinary disturbances, scoliosis, pes cavus, optic atrophy, amyotrophy, cortical atrophy, impaired vibration sensation in the lower limbs, dysarthria, dysphagia, cerebellar and extrapyramidal symptoms, cognitive disorders. Mutations in SPG7 are thought to be transmitted in an autosomal recessive manner, but families with autosomal dominant inheritance of the genetic variant p.L78* have also been reported. In our country, this genetic variant was found in patients with Roma ethnicity.

Reasons for referring:
Reasons for referring - Autosomal recessive type of inheritance, pure or complex form of the disease with sphincter disorders, urinary incontinence, cerebellar symptoms, amyotrophy, extrapyramidal symptoms.

Confirmation of diagnosis; Making a diagnosis; Determining the risk of developing the disease.

Autosomal recessive type of inheritance, pure or complex form of the disease with sphincter disorders, urinary incontinence, cerebellar symptoms, amyotrophy, extrapyramidal symptoms.

Interpretation of results:

-          Identification of the point mutation p.L78X in the SPG7 gene will allow a genetic diagnosis of SPG7-related hereditary spastic paraplegia.

-          The absence of this mutation does not rule out the diagnosis of SPG7-related hereditary spastic paraplegia. It is possible that the disease is due to other point mutations, small deletions/insertions in the SPG7 gene. Presence of large deletions and insertions cannot be detected by this method. A combination with a suitable CNV analysis (MLPA, aCGH) is recommended for their detection.

-          The genetic counselor will interpret and answer all questions you may have about your result.

Method: Sanger sequencing.

The method involves bi-directional DNA sequencing of exon 2 and the adjacent intron-exon boundaries in the SPG7 gene. The laboratory offers single exon sequencing in relatives of patients to determine carrier status in cases where the mutation is known (Test #182).

Sensitivity of the method: 99.5%

What does the test involve?

-          DNA isolation and sample storage.

-          Direct sequencing of exon 2 encompassing p.L78*.

-          Forming a written result of the genetic test.

-          Diagnostic interpretation of results and genetic counseling.

Biological material: Venous blood or DNA

For more information, please read the "Biological material requirements and shipping information" carefully.