Stiff-person syndrome

Stiff-person disease
Stiff-person disease
	Photomicrograph of cerebellum with bound anti-GAD65 monoclonal antibodies (green), indirect immunofluorescence
Specialty	Neurology
Symptoms	muscular rigidity and trigger-induced painful muscle spasms
Frequency	1 in 1,000,000

Stiff-person syndrome (SPS), also known as stiff-man syndrome,^[1] is a rare neurological disorder of unclear cause characterized by progressive muscular rigidity and stiffness. The stiffness primarily affects the truncal muscles and is characterised by spasms, resulting in postural deformities. Chronic pain, impaired mobility, and lumbar hyperlordosis are common symptoms.^[2]^[3]

SPS occurs in about one in a million people and is most commonly found in middle-aged people. A small minority of patients have the paraneoplastic variety of the condition. Variants of the condition, such as stiff-limb syndrome, which primarily affects a specific limb, are often seen.

SPS was first described in 1956. Diagnostic criteria were proposed in the 1960s and refined two decades later. In the 1990s and 2000s, the role of antibodies in the condition became clearer. SPS patients generally have glutamic acid decarboxylase (GAD) antibodies, which seldom occur in the general population. In addition to blood tests for GAD, electromyography tests can help confirm the condition's presence.

Benzodiazepine-class drugs are the most common treatment; they are used for symptom relief from stiffness. Other common treatments include baclofen, intravenous immunoglobin, and rituximab. Limited but encouraging therapeutic experience of haematopoietic stem cell transplantation exists for SPS.^[2]

^ Darras BT, Jones Jr HR, Ryan MM (2014). Neuromuscular Disorders of Infancy, Childhood, and Adolescence. Elsevier Science. p. 188. ISBN 978-0-12-417127-5. The stiff-man syndrome (SMS, also known as stiff-person syndrome) is a rare central nervous system autoimmune disease, but is likely underrecognized.
^ ^a ^b "Stiff-Person Syndrome | National Institute of Neurological Disorders and Stroke". www.ninds.nih.gov. Retrieved 2023-01-18.
^ "Stiff person syndrome - About the Disease - Genetic and Rare Diseases Information Center". rarediseases.info.nih.gov. Archived from the original on 2022-11-15. Retrieved 2023-01-18.

[Darras2014-1] Darras BT, Jones Jr HR, Ryan MM (2014). Neuromuscular Disorders of Infancy, Childhood, and Adolescence. Elsevier Science. p. 188. ISBN 978-0-12-417127-5. The stiff-man syndrome (SMS, also known as stiff-person syndrome) is a rare central nervous system autoimmune disease, but is likely underrecognized.

[ninds.nih.gov-2] "Stiff-Person Syndrome | National Institute of Neurological Disorders and Stroke". www.ninds.nih.gov. Retrieved 2023-01-18.

[3] "Stiff person syndrome - About the Disease - Genetic and Rare Diseases Information Center". rarediseases.info.nih.gov. Archived from the original on 2022-11-15. Retrieved 2023-01-18.

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