Musculoskeletal deformities of Alström syndrome-a review of 55 cases.

INTRODUCTION

Alström syndrome (ALMS) is an ultra-rare metabolic disorder caused by biallelic loss-of-function in the Alms1 gene which encodes a ubiquitously expressed centrosomal protein of the primary cilium. Dual sensory defects, several metabolic and hormonal dysfunctions are frequent in ALMS. Increased musculoskeletal deformities have been observed, though these aspects have not been systematically reviewed. This study characterises the anthropometric, clinical, genetic and imaging features of bone deformities in a large UK cohort with ALMS and describes the details of first documented successful corrective surgery for scoliosis.

METHODS

A preliminary study of 13 Alström patients was undertaken to evaluate musculoskeletal deformities. Written consent was obtained after sharing of study information via voice mail or Braille. Questionnaires, clinical examination and radiological evaluations were conducted twice 12 months apart by a rheumatologist and an orthopaedic surgeon. Two patients had scoliosis which required intervention. To discover its prevalence, 42 further AS patients were reviewed. All patients attended the Alstom syndrome UK specialist clinics.

RESULTS

In the detailed survey of 13 patients, all had some degree of musculoskeletal deformities, most commonly partially correctable thoracic kyphosis, brachydactyly, femoral anteversion and pes planus but rarely affecting their daily functioning. In the larger group of 55 patients, 6 had scoliosis requiring intervention; two of whom had spinal deformity requiring surgical correction in adolescence, and one had cervical spine surgery for spondylitis.

CONCLUSION

ALMS patients tend to have high prevalence of musculoskeletal deformities which may be part of the ciliopathy. Postural adaptation to dual sensory loss resulted in correctable kyphosis, treatable by physiotherapy. Scoliosis requiring intervention is frequent (10.9%), with successful surgery undertaken where indicated.