Multifocal Motor Neuropathy, or MMN, is an incurable immune-mediated disorder, which causes muscle weakness that worsens over time.1,2 MMN commonly begins in the finger, thumb, wrist or lower leg.3,4 It affects the strength in the lower parts of the arms and hands more than the legs, usually without affecting touch sensation.1 MMN usually causes weakness in one side of the body (asymmetrical).4

It is thought that with MMN, immune system abnormalities affect the protective layer (myelin sheath) around nerve cells that control muscle function. The protective layer normally allows messages to be sent properly and quickly throughout the nervous system. When the protective layer breaks down (a process called demyelination), nerve damage can occur. When nerve impulses are interrupted, muscle weakness can occur.4,5

MMN is a rare, often difficult to diagnose disorder. Some symptoms of MMN are similar to those of other types of peripheral nerve disorders.6 The diagnosis of MMN often is based on a physical exam, an evaluation of symptoms, an electromyography (EMG) test, nerve conduction study, laboratory tests, MRI, and medical history.4,6

Your healthcare provider may also request a blood test or order other tests to fully understand your health status.4,6

While the exact cause of MMN is unknown, it is thought that immune system abnormalities affect the protective layer around nerve cells that control muscle function. In a normal nerve, the protective layer (myelin sheath) allows messages to be sent properly and quickly throughout the nervous system (Figure 1). When the protective layer (myelin sheath) breaks down (a process called demyelination), nerve damage can occur (Figure 2). When nerve impulses are interrupted, muscle weakness can occur.4,5

Normal peripheral nerve illustration

Figure 1: Normal peripheral nerve

Damaged peripheral nerve illustration

Figure 2: Damaged peripheral nerve

What it is

  • Chronic, treatable, but incurable immune-mediated disorder that affects nerves and muscles2
  • Associated with muscle weakness affecting the hands, forearms, and lower legs that can interfere with daily living4,8
  • Rare, often difficult to diagnose condition characterized by slow progressive asymmetric distal limb weakness4

What it is not

  • Fatal6
  • Amyotrophic lateral sclerosis (ALS) or Lou Gehrig's disease4,6
  • A nerve compression condition, such as carpal tunnel sydrome2,6

GAMMAGARD LIQUID [Immune Globulin Infusion (Human)] 10% is made from human plasma that is donated by healthy people. GAMMAGARD LIQUID contains antibodies collected from these healthy people. The role of these antibodies and the mechanisms of action of IgG in GAMMAGARD LIQUID in the treatment of MMN is not fully understood.1


  1. GAMMAGARD LIQUID [Immune Globulin Infusion (Human)] 10% [Prescribing Information]. Westlake Village, CA: Baxalta US Inc.
  2. Katirji B, Koontz D. Disorders of peripheral nerves. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:1915-2015.
  3. Slee M, Selvan A, Donaghy M. Multifocal motor neuropathy: the diagnostic spectrum and response to treatment. Neurology. 2007;69(17):1680-1687.
  4. Vlam L, van der Pol WL, Cats EA, et al. Multifocal motor neuropathy: diagnosis, pathogenesis and treatment strategies. Nat Rev Neurol. 2012;8(1):48-58.
  5. Piepers S, Jansen MD, Cats EA, van Sorge NM, van den Berg LH, van der Pol WL. IVIg inhibits classical pathway activity and anti-GM1 IgM-mediated complement deposition in MMN. J Neuroimmunol. 2010;229(1-2):256-262.
  6. Meuth SG, Kleinschnitz C. Multifocal motor neuropathy: update on clinical characteristics, pathophysiological concepts and therapeutic options. Eur Neurol. 2010;63(4):193-204.
  7. Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:2396-2409.
  8. Sharrack B, Hughes RA. The Guy's Neurological Disability Scale (GNDS): a new disability measure for multiple sclerosis. Mult Scler. 1999;5(4):223-233.


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Selected Important Safety Information about GAMMAGARD LIQUID
  • GAMMAGARD LIQUID can cause decreased kidney function or kidney failure, blood clots in the heart, brain, lungs or elsewhere in the body. Call your healthcare professional or go to your emergency department right away if you have: Reduced urination, sudden weight gain, or swelling in your legs. These could be signs of a kidney problem. Pain, swelling, warmth, redness, or a lump in your legs or arms. These could be signs of a blood clot.
  • Do not take GAMMAGARD LIQUID if you have a known history of a severe allergic reaction to IgG or other blood products.