Mutation spectrum of EXT1 and EXT2 in the Saudi patients with hereditary multiple exostoses.

BACKGROUND: Hereditary Multiple Exostoses (HME), also known as Multiple Osteochondromas (MO) is a rare genetic disorder characterized by multiple benign cartilaginous bone tumors, which are caused by mutations in the genes for exostosin glycosyltransferase 1 (EXT1) and exostosin glycosyltransferase 2 (EXT2). The genetic defects have not been studied in the Saudi patients. AIM OF STUDY: We investigated mutation spectrum of EXT1 and EXT2 in 22 patients from 17 unrelated families. METHODS: Genomic DNA was extracted from peripheral leucocytes. The coding regions and intron-exon boundaries of both EXT1 and EXT2 genes were screened for mutations by PCR-sequencing analysis. Gross deletions were analyzed by MLPA analysis. RESULTS: EXT1 mutations were detected in 6 families (35%) and 3 were novel mutations: c.739G > T (p. E247*), c.1319delG (p.R440Lfs*4), and c.1786delA (p.S596Afs*25). EXT2 mutations were detected in 7 families (41%) and 3 were novel mutations: c.541delG (p.D181Ifs*89), c.583delG (p.G195Vfs*75), and a gross deletion of approximately 10 kb including promoter and exon 1. Five patients from different families had no family history and carried de novo mutations (29%, 5/17). No EXT1 and EXT2 mutations were found in the remaining four families. In total, EXT1 and EXT2 mutations were found in 77% (13/17) of Saudi HME patients. CONCLUSION: EXT1 and EXT2 mutations contribute significantly to the pathogenesis of HME in the Saudi population. In contrast to high mutation rate in EXT 1 (65%) and low mutation rate in EXT2 (25%) in other populations, the frequency of EXT2 mutations are much higher (41%) and comparable to that of EXT1 among Saudi patients. De novo mutations are also common and the six novel EXT1/EXT2 mutations further expands the mutation spectrum of HME.

Psoas Hematoma and Late Femoral Nerve Palsy After Extreme Lateral Interbody Fusion and Posterior Spinal Fusion with Instrumentation: A Case Report.

INTRODUCTION: Psoas hematoma is an uncommon complication following spinal surgeries. It has been reported in both extreme lateral interbody fusion (XLIF) and posterior spinal fusion with instrumentation. Minimally invasive techniques are gaining popularity in recent years due to the appealing advantages of reduced operative time, blood loss, hospital stay, and faster recovery. CASE PRESENTATION: We are presenting a case of a 77-year-old male with chronic low back pain, diagnosed to have multilevel degenerative disc disease with central and foraminal disc protrusion at L2-L3, L3-L4, L4-L5 with secondary spinal stenosis, underwent XLIF at L3-L4, L4-L5 and then 2nd stage with posterior L3-L5 fusion with pedicle screws. On the fourth day post-operatively, the patient had flank pain and dropping hemoglobin with femoral nerve palsy symptoms, a CT scan revealed a large psoas hematoma. Conservative management was decided on; a follow-up CT scan and examination showed complete resolution of the hematoma and femoral nerve recovery. DISCUSSION: The approach to iliopsoas hematoma post spinal surgeries remains controversial. Iliopsoas hematoma should be suspected in any patients post spinal surgeries even with delayed presentations. The decision to proceed with either surgical intervention or conservative management depends on multiple factors, including patient hemodynamic status, progression of collection and femoral nerve palsy. CONCLUSION: The exact cause of iliopsoas hematoma post different spinal surgery approaches remains vague. In our opinion, other causes including pre- and post-operative anticoagulants should be investigated. Rushing to drain iliopsoas hematomas in case of femoral nerve palsy might not be the ideal option. Instead, monitoring patient responses to resuscitation and taking a watch and wait approach for femoral nerve palsy might be the proper approach.