Maternal myasthenia gravis: a cause for arthrogryposis multiplex congenita.
BACKGROUND
Arthrogryposis multiplex congenita (AMC) is a condition defined as contractures in more than two joints and in multiple body areas. The principal mechanism leading to the development of AMC in utero is decreased fetal movement.


OBJECTIVE
Both fetal and maternal factors can lead to this condition, including maternal myasthenia gravis (MG) which is the topic of this review. MG is an autoimmune disease in which antibodies (immunoglobulin G) are formed against acetylcholine receptors. The disease can affect both genders, but women are more prone to develop the disease in early adulthood, a phase of life when the focus of many women is often directed towards founding a family. During pregnancy, maternal antibodies are transmitted to the fetus.


RESULTS
Although the child is unaffected in most cases, the constant transmission of antibodies in utero can lead to neonatal myasthenia post-partum, a transient condition characterized by hypotonia and swallowing/respiratory difficulties as well as AMC.


CONCLUSIONS
The maternal antibody profile in mothers with MG seems to play a key role in whether the child develops AMC or not. There are also indications that there may be a relation between neonatal MG and AMC, as well as a high recurrence rate in siblings.
Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway. jmid@helse-bergen.no.
Jana
J
Midelfart Hoff
Faculty of Medicine, Norwegian University of Science and Technology (NTNU), 7000, Trondheim, Norway.
Anna
A
Midelfart
AMC; Autoimmune disease; Myasthenia gravis; Neonatal myasthenia gravis