Severe neonatal myasthenia due to maternal anti-MuSK antibodies.
Anti-MuSK antibodies have been reported in about 40-50% of patients with seronegative myasthenia gravis. Curiously, this condition has never been reported in association with fetal or transient neonatal myasthenia gravis, despite a known female predominance. We report the case of a 22-year-old woman who developed seronegative, mild steroid-responsive myasthenia gravis. When aged 26, she gave birth to a baby boy with neonatal myasthenia gravis characterized by hypotonia, stridor and sucking difficulties. Intubation was required for a few weeks. Anti-MuSK antibodies were assessed and found positive in both patients. Progressive hydramnios during the last trimester, with a decrease in spontaneous fetal mobility in the last weeks, long-lasting stridor, ptosis and occasional difficulties in swallowing liquids till two years of age, despite anti-MuSK antibodies becoming negative, suggest a fetal onset. The possible pathophysiology of this disorder, based on recent findings on the expression and function of MuSK protein, is reviewed.
Béhin
Anthony
A
Centre de Référence des maladies rares neuromusculaires Paris-Est, Institut de Myologie, Service de Neurologie Mazarin, Groupe Hospitalier Pitié-Salpêtrière, APHP, 47-83 Boulevard de l'hôpital, 75651 Paris Cedex 13, France. anthony.behin@psl.aphp.fr
Mayer
Michèle
M
Kassis-Makhoul
Bouchera
B
Jugie
Myriam
M
Espil-Taris
Caroline
C
Ferrer
Xavier
X
Chatenoud
Lucienne
L
Laforêt
Pascal
P
Eymard
Bruno
B
D000328:Adult; D000906:Antibodies / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D009034:Mother-Child Relations; D009157:Myasthenia Gravis / Q000139:chemically induced*; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology*; D011950:Receptors, Cholinergic / Q000276:immunology*
D000906:Antibodies; D011950:Receptors, Cholinergic; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases