Multiplex Ligation Dependent Probe Amplification Based Mutation Analysis of Dystrophin Gene in Nepalese Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is X-linked recessive neuromuscular disorders caused due to mutation in dystrophin gene, leading to progressive muscle weakness. This study was done to identify mutation in dystrophin gene in Nepalese patients with DMD using Multiplex Ligation Dependent Probe Amplification (MLPA) assay in Nepal. Twenty one patients from different regions of Nepal, who were clinically diagnosed as DMD were enrolled in the study. Peripheral blood samples were collected in EDTA vials, gDNA was extracted, and deletion mutation in the dystrophin gene was analysed using Multiplex Ligation Dependent Probe Amplification (MLPA) assay.Exon deletion mutation in the dystrophin gene was observed in 14 (66.6%) out of 21 DMD cases. The most common exon deletion was observed and confined in exon 7-14 and 45-53 of dystrophin gene. The location of deletion in dystrophin gene is apparently non-random with a preponderance found in the hot spot regions. Use of MLPA is useful in detecting copy number changes in DMD proband and suspected carriers in Nepal

Nerve Root Sedimentation Sign among Lumbar Canal Stenosis Patients Visiting the Department of Orthopaedics in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction: Lumbar canal stenosis is a common cause of back pain and neurogenic claudication in the elderly population. Nerve root sedimentation sign-on Magnetic resonance imaging is a novel sign proposed for the diagnosis of lumbar canal stenosis. There is limited research so far. So, the aim of this study was to find out the prevalence of nerve root sedimentation signs in lumbar canal stenosis among patients visiting the Department of Orthopaedics in a tertiary care centre. Methods: This was a descriptive cross-sectional study conducted from 1 January 2020 to 31 July 2021 in the tertiary care centre, after receiving ethical approval from the Institutional ethical review board (Reference number: 299/(6-11)076/077). The anteroposterior diameter of the dural sac at the most stenotic level and nerve root sedimentation sign in magnetic resonance images were measured in patients with lumbar canal stenosis. Point estimate and 95% Confidence Interval were calculated. Results: Among 40 patients enrolled, 34 (85%) (84.01-85.99, 95% Confidence Interval) patients had positive nerve root sedimentation sign. Out of 34 (85%) cases with positive sedimentation signs, 32 (94.12%) had severe lumbar stenosis and the remaining 2 (5.88%) had moderate lumbar stenosis. Conclusions: The prevalence of nerve root sedimentation signs is similar to the similar studies done in similar settings. Nerve root sedimentation signs on magnetic resonance imaging can be used as an objective sign for the diagnosis of severe lumbar canal stenosis

Molecular Confirmation of G1138A Mutation in FGFR gene in Achondroplasia

Introduction: Achondroplasia (ACH) is the most common form of skeletal dysplasia of genetic origin in humans which is characterized by disproportionate rhizomelic dwarfism. Heterozygous mutation in the transmembrane domain of the FGFR3 gene (4p16.3) occurs as a de novo mutation in most of the cases.  Methods: DNA was isolated from seven samples, out of which, five had clinical features of Achondroplasia while one was dwarf but did not show symptoms of the disorder and one as negative control. PCR was performed for the region incorporating the hotspot region viz. 1138th nucleotide. PCR amplicon of size 164 bp was obtained from all the samples, and was sequenced. Results: Sequence analysis showed the presence of mutation (G to A transition) in all of the five samples. The five samples that showed the clinical features of Achondroplasia had mutation in the region being analyzed while the single patient who had no clinical manifestations of the disorder despite being dwarf had no such mutation. Among the five patients studied, one patient had a family history of Achondroplasia as observed through pedigree analysis while the remaining four cases were sporadic in nature.  Conclusions: This study further supports that the G1138A mutation is the one of the most common point mutation among Achondroplasia cases. Genetic diagnosis can be useful to identify the disease prenatally and differentiate other life threatening dwarfism for the safety of both mother and fetus.  Keywords: achondroplasia; dwarfism; fibroblast growth factor receptor 3 (FGFR3); point Mutation

Is lumbar facet joint tropism developmental or secondary to degeneration? An international, large-scale multicenter study by the AOSpine Asia Pacific Research Collaboration Consortium

Background: Facet joint tropism is asymmetry in orientation of the bilateral facets. Some studies have shown that tropism may increase the risk of disc degeneration and herniations, as well as degenerative spondylolisthesis (DS). It remains controversial whether tropism is a pre-existing developmental phenomena or secondary to progressive remodeling of the joint structure due to degenerative changes. As such, the following study addressed the occurrence of tropism of the lower lumbar spine (i.e. L3-S1) in a degenerative spondylolisthesis patient model. Methods: An international, multi-center cross-sectional study that consisted of 349 patients with single level DS recruited from 33 spine institutes in the Asia Pacific region was performed. Axial MRI/CT from L3-S1 were utilized to assess left and right facet joint sagittal angulation in relation to the coronal plane. The angulation difference between the bilateral facets was obtained. Tropism was noted if there was 8° or greater angulation difference between the facet joints. Tropism was noted at levels of DS and compared to immediate adjacent and distal non-DS levels, if applicable, to the index level. Age, sex-type and body mass index (BMI) were also noted and assessed in relation to tropism. Results: Of the 349 subjects, there were 63.0 % females, the mean age was 61.8 years and the mean BMI was 25.6 kg/m. Overall, 9.7, 76.5 and 13.8 % had L3-L4, L4-L5 and L5-S1 DS, respectively. Tropism was present in 47.1, 50.6 and 31.3 % of L3-L4, L4-L5 and L5-S1 of levels with DS, respectively. Tropism involved 33.3 to 50.0 % and 33.3 to 58.8 % of the immediate adjacent and most distal non-DS levels from the DS level, respectively. Patient demographics were not found to be significantly related to tropism at any level (p > 0.05). Conclusions: To the authors' knowledge, this is one of the largest studies conducted, in particular in an Asian population, addressing facet joint tropism. Although levels with DS were noted to have tropism, immediate adjacent and distal levels with no DS also exhibited tropism, and were not related to age and other patient demographics. This study suggests that facet joint tropism or perhaps subsets of facet joint orientation may have a pre-disposed orientation that may be developmental in origin or a combination with secondary changes due to degenerative/slip effects. The presence of tropism should be noted in all imaging assessments, which may have implications in treatment decision-making, prognostication of disease progression, and predictive modeling. Having a deeper understanding of such concepts may further elaborate on the precision phenotyping of the facets and their role in more personalized spine care. Additional prospective and controlled studies are needed to further validate the findings

Critical values of facet joint angulation and tropism in the development of lumbar degenerative spondylolisthesis: an international, large-scale multicenter study by the AOSpine Asia Pacific Research Collaboration Consortium

Study Design An international, multicenter cross-sectional image-based study performed in 33 institutions in the Asia Pacific region. Objective The study addressed the role of facet joint angulation and tropism in relation to L4-L5 degenerative spondylolisthesis (DS). Methods The study included 349 patients (63% females; mean age: 61.8 years) with single-level DS; 82 had no L4-L5 DS (group A) and 267 had L4-L5 DS (group B). Axial computed tomography and magnetic resonance imaging were utilized to assess facet joint angulations and tropism (i.e., asymmetry between facet joint angulations) between groups. Results There was a statistically significant difference between group A (left mean: 46.1 degrees; right mean: 48.2 degrees) and group B (left mean: 55.4 degrees; right mean: 57.5 degrees) in relation to bilateral L4-L5 facet joint angulations (p < 0.001). The mean bilateral angulation difference was 7.4 and 9.6 degrees in groups A and B, respectively (p = 0.025). A critical value of 58 degrees or greater significantly increased the likelihood of DS if unilateral (adjusted OR: 2.5; 95% CI: 1.2 to 5.5; p = 0.021) or bilateral facets (adjusted OR: 5.9; 95% CI: 2.7 to 13.2; p < 0.001) were involved. Facet joint tropism was found to be relevant between 16 and 24 degrees angulation difference (adjusted OR: 5.6; 95% CI: 1.2 to 26.1; p = 0.027). Conclusions In one of the largest studies assessing facet joint orientation in patients with DS, greater sagittal facet joint angulation was associated with L4-L5 DS, with a critical value of 58 degrees or greater increasing the likelihood of the condition for unilateral and bilateral facet joint involvement. Specific facet joint tropism categories were noted to be associated with DS