P096 Munchmeyer's disease: an unknown pathology

Abstract

Abstract Background Munchmeyer's disease (MM) or Fibrodysplasia ossificans progressivais an extremely rare genetic disorder characterized by heterotopic ossification of muscle and connective tissue during flare-ups, which can lead to the creation of a true second skeleton. we report an original observation with diagnostic difficulty. Observation We report the case of 37-year-old women who consulted for cervical stiffness with painful hypertrophy of the left sternocleidomastoid muscle, dorsal scoliosis, tendon retractions in limbs with a semi-flexion attitude. In addition, she presented a deformity of the forefoot with hallux valgus and a triangular shape. X-ray of the right arm showed ossification of the biceps brachii and that of the foot showed interphalangeal ankyloses with agenesis of a phalanx of the big toe. X-rays of the cervical spine revealed posterior arch ankyloses with fusion of some vertebrae. Despite the late onset of symptoms, the diagnosis of MM was suggested and confirmed by a genetic study which revealed a heterozygous c.617G> A [p. Arg206His] mutation, located in exon 6 of the gene. Conclusion MM is an extremely rare but disabling condition. It should be considered in unexplained muscle enlargement occurring at any age particularly if associated with congenital malformations of the Hallux. The discovery of the ACVR1 gene mutation offers hope for the development of therapies for this hitherto incurable disease.