Multiple Synostoses Syndrome

At a glance

It is a medical condition that is characterized by multiple joint fusions, usually commencing in the hands, conductive deafness, and characteristic facial features, including a broad, tubular-shaped nose, and a thin upper vermilion. Clinically, physical features include brachydactyly, hypoplastic or absent middle phalanges, radial head dislocation, and pectus carinatum. It also affects the cervical spine and can become a major consideration in anesthesia.

Synonyms

Polysynostosis Syndrome; Synostosis Multiplex; Symphalangism Brachydactyly Syndrome; WL Syndrome; Deafness Symphalangism Syndrome of Herrman; Facioaudiosymphalangism Syndrome; Herrman Syndrome.

History

This medical condition was first described by Fuhrmann et al, in 1966 who described the physical characteristics observed with the mother and her son. They included bilateral dysplasia, elbow, finger wrist and foot synostoses, and short middle phalanges and metacarpals.

Incidence

The exact incidence and prevalence remains unknown. There are few cases reported in the literature, mostly from China. The onset of the disease is believed during childhood.

Genetic inheritance

Familial and/or autosomal dominant inheritance. Chromosome 17q 21-22 has been linked to the disease. Fibroblast growth factors (FGFs) play diverse roles in several developmental processes. Mutations leading to deregulated FGF signaling can cause human skeletal dysplasias. Biochemical analysis reveals that S99N mutation in FGF9 leads to significantly impaired FGF signaling. It is believed associated with abnormal joint development.

Pathophysiology

Symphalangism, synostoses of the tarsal and carpal bones, and other abnormalities, including orofacial defects and delayed mental development, occurring alone or as a component of other syndromes.

Diagnosis

Numerous skeletal deformities should evoke the diagnosis.

Clinical aspects

Hand abnormalities include synostoses of the carpal bones, radial head subluxation, hypoplasia of the middle phalanges, and metacarpophalangeal synostoses; short and broad first metacarpal bones, disturbances in bone modeling of the metacarpal bones and phalanges, and agenesis of the middle phalanges. Foot abnormalities include synostoses of the tarsal bones, synostoses of the tarsal and metatarsal bones, agenesis of the middle and distal phalanges, and disturbance in bone modeling of the phalanges. Hypoplasia of the alae nasi. Short upper lip. Cubitus valgus, limited extension of the forearm, and limited hip motion. Variable fusion of middle ear ossicles. Moderate mental retardation.

Precautions before anesthesia

Complete neurologic and motor examination encompassing milestones, parental information, and chart information. The possibility of cervical spine synostosis can be a significant consideration and a complete examination of head mobility will be needed before anesthesia. It is always wise to ensure that there is no other syndrome associated and for which anesthesia implications could be considerable. If the patient receives chronic corticosteroid treatment, preoperative supplementation is indicated.

Anesthetic considerations