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In 1987 Fitzsimmons and Guilbert described identical male twins with progressive spastic paraplegia, brachydactyly with cone shaped epiphyses, short stature, dysarthria, and 'low-normal' intelligence. In subsequent years, four other patients, including one set of female identical twins, a single female child, and a single male individual were described with the same features, and the eponym Fitzsimmons syndrome was adopted (OMIM #270710). We performed exome analysis of the patient described in 2009, and one of the original twins from 1987, the only patients available from the literature. No single genetic etiology exists that explains Fitzsimmons syndrome; however, multiple different genetic causes were identified. Specifically, the twins described by Fitzsimmons had heterozygous mutations in the SACS gene, the gene responsible for autosomal recessive spastic ataxia of Charlevoix Saguenay (ARSACS), as well as a heterozygous mutation in the TRPS1, the gene responsible in Trichorhinophalangeal syndrome type 1 (TRPS1 type 1) which includes brachydactyly as a feature. A TBL1XR1 mutation was identified in the patient described in 2009 as contributing to his cognitive impairment and autistic features with no genetic cause identified for his spasticity or brachydactyly. The findings show that these individuals have multiple different etiologies giving rise to a similar phenotype, and that 'Fitzsimmons syndrome' is in fact not one single syndrome. Over time, we anticipate that continued careful phenotyping with concomitant genome-wide analysis will continue to identify the causes of many rare syndromes, but it will also highlight that previously delineated clinical entities are, in fact, not syndromes at all. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Limb girdle muscular dystrophy ( LGMD) is a heterogeneous group of genetic disorders leading to progressive muscle degeneration and often associated with cardiac complications. We present two adult siblings with childhood-onset of weakness progressing to a severe quadriparesis with the additional features of triangular tongues and biventricular cardiac dysfunction. Whole exome sequencing identified compound heterozygous missense mutations that are predicted to be pathogenic in LIMS2. Biopsy of skeletal muscle demonstrated disrupted immunostaining of LIMS2. This is the first report of mutations in LIMS2 and resulting disruption of the integrin linked kinase ( ILK)- LIMS-parvin complex associated with LGMD. [ABSTRACT FROM AUTHOR]