National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Spastic paraplegia 2



Other Names:
SPG2; SPPX2
Categories:

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 99015

Definition
A rare, X-linked leukodystrophy characterized primarily by spastic gait and autonomic dysfunction. When additional central nervous system (CNS) signs, such as intellectual deficit, ataxia, or extrapyramidal signs, are present, the syndrome is referred to as complicated SPG.

Epidemiology
The prevalence and incidence of SPG2 have not been reported, but as part of the Pelizaeus-Merzbacher (PMD; see this term) spectrum, SPG2 roughly accounts for about 20 % of cases. There have been approximately 20 cases published on SPG2. SPG2 affects males but some female heterozygotes presenting in adulthood with a milder phenotype have also been reported.

Clinical description
SPG2 spans a continuum of phenotypes that goes from pure to complicated SPG2. Pure SPG2 manifests as early as infancy or early childhood (<5 years) but may be delayed until early adulthood. It presents with weakness, hyperreflexia, Babinski sign and spastic gait due to spastic paraparesis. Autonomic dysfunction (spastic urinary bladder and possibly bowel, with increased urinary and fecal frequency and incontinence) is frequent. Patients are able to walk and their speech is normal. There is no CNS involvement and no cognitive decline. Complicated SPG2 shares the same features as SPG2 but also shows additional CNS involvement like nystagmus, and ataxia that present in the first years of life. Optic atrophy may be present. Patients can also show a mild intellectual deficit.

Etiology
SPG2 is due to missense substitutions affecting the PLP1 gene. PLP1 encodes the proteolipid protein (PLP), the most abundant protein of the myelin sheath in the central nervous system, and its alternatively spliced isoform (DM20). SPG2 is allelic to Pelizaeus-Merzbacher disease (PMD; see this term) that is also due to PLP1 mutations.

Diagnostic methods
Diagnosis is based on clinical, electrophysiologic, and neuroradiological findings. White matter N-acetyl aspartate levels are reduced. Brain magnetic resonance imaging (MRI) reveals patchy or diffuse hypomyelination on T2-weighted images. Patients with pure SPG2 can have very subtle T2 hyperintensity. Other MR techniques, including MR spectroscopy and diffusion tensor imaging are useful in the diagnosis of the disease. Molecular genetic testing of PLP1 confirms the diagnosis.

Differential diagnosis
Differential diagnosis includes other forms of hereditary spastic paraplegia (see this tem). Complicated SPG2 is not clearly distinguishable from mild Pelizaeus-Merzbacher disease (PMD) and null syndrome (see these terms).

Antenatal diagnosis
Prenatal genetic testing is possible when a family's underlying PLP1 mutation has been identified.

Genetic counseling
Transmission is X-linked recessive.

Management and treatment
A son born to a female carrier has a 50% risk of inheriting the mutation and developing the disease, while a daughter has a 50% risk of being a carrier. All daughters of an affected male will be carriers but none of his sons will be affected. Management is multidisciplinary and involves neurologists, physical therapists, and orthopedic doctors. Treatment may include antiepileptic drugs for seizures, and physical therapy with antispasticity drugs (baclofen, diazepam, tizanidine, botulinum toxin, dantrolene) for spasticity. Regular surveillance is necessary.

Prognosis
Pure SPG2 patients show a normal life expectancy. In complicated SPG2 cases, patients deteriorate neurologically leading to a shorter life expectancy (between the fourth and seventh decade) typically from aspiration pneumonia, pulmonary embolism and other complications of generalized weakness.

Visit the Orphanet disease page for more resources.
Last updated: 10/1/2011

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 29 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Babinski sign 0003487
Hyperreflexia
Increased reflexes
0001347
Muscle weakness
Muscular weakness
0001324
Spastic gait
Spastic walk
0002064
30%-79% of people have these symptoms
Abnormality of extrapyramidal motor function 0002071
Bowel incontinence
Loss of bowel control
0002607
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ]
0001249
Optic atrophy 0000648
Spastic/hyperactive bladder 0005340
5%-29% of people have these symptoms
Ataxia 0001251
Dysarthria
Difficulty articulating speech
0001260
Limitation of joint mobility
Decreased joint mobility
Decreased mobility of joints
Limited joint mobility
Limited joint motion
[ more ]
0001376
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Pulmonary embolism
Blood clot in artery of lung
0002204
Recurrent respiratory infections
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections
[ more ]
0002205
Sensory neuropathy
Damage to nerves that sense feeling
0000763
Percent of people who have these symptoms is not available through HPO
Abnormal cerebellum morphology
Abnormality of the cerebellum
Cerebellar abnormalities
Cerebellar abnormality
Cerebellar anomaly
[ more ]
0001317
Degeneration of the lateral corticospinal tracts 0002314
Dysmetria
Lack of coordination of movement
0001310
Flexion contracture
Flexed joint that cannot be straightened
0001371
Juvenile onset
Signs and symptoms begin before 15 years of age
0003621
Lower limb muscle weakness
Lower extremity weakness
Lower limb weakness
Muscle weakness in lower limbs
[ more ]
0007340
Lower limb spasticity 0002061
Pes cavus
High-arched foot
0001761
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting
[ more ]
0003202
Spastic paraparesis 0002313
Spastic paraplegia 0001258
Spinocerebellar tract degeneration 0002503
X-linked recessive inheritance 0001419
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Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Social Networking Websites

  • RareConnect is an online social network for patients and families to connect with one another and share their experience living with a rare disease. The project is a joint collaboration between EURORDIS (European Rare Disease Organisation) and NORD (National Organization for Rare Disorders). Click on the link above to view the community for Hereditary spastic paraplegia.

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Spastic paraplegia 2. Click on the link to view a sample search on this topic.

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