Mobility shift of beta-dystroglycan as a marker of GMPPB gene-related muscular dystrophy

BACKGROUND

Defects in glycosylation of alpha-dystroglycan (α-DG) cause autosomal-recessive disorders with wide clinical and genetic heterogeneity, with phenotypes ranging from congenital muscular dystrophies to milder limb girdle muscular dystrophies. Patients show variable reduction of immunoreactivity to antibodies specific for glycoepitopes of α-DG on a muscle biopsy. Recessive mutations in 18 genes, including guanosine diphosphate mannose pyrophosphorylase B (GMPPB), have been reported to date. With no specific clinical and pathological handles, diagnosis requires parallel or sequential analysis of all known genes.

METHODS

We describe clinical, genetic and biochemical findings of 21 patients with GMPPB-associated dystroglycanopathy.

RESULTS

We report eight novel mutations and further expand current knowledge on clinical and muscle MRI features of this condition. In addition, we report a consistent shift in the mobility of beta-dystroglycan (β-DG) on Western blot analysis of all patients analysed by this mean. This was only observed in patients with GMPPB in our large dystroglycanopathy cohort. We further demonstrate that this mobility shift in patients with GMPPB was due to abnormal N-linked glycosylation of β-DG.

CONCLUSIONS

Our data demonstrate that a change in β-DG electrophoretic mobility in patients with dystroglycanopathy is a distinctive marker of the molecular defect in GMPPB.

Cerebral aneurysms treated with flow-diverting stents: computational models with intravascular blood flow measurements

BACKGROUND AND PURPOSE

Computational fluid dynamics modeling is useful in the study of the hemodynamic environment of cerebral aneurysms, but patient-specific measurements of boundary conditions, such as blood flow velocity and pressure, have not been previously applied to the study of flow-diverting stents. We integrated patient-specific intravascular blood flow velocity and pressure measurements into computational models of aneurysms before and after treatment with flow-diverting stents to determine stent effects on aneurysm hemodynamics.

MATERIALS AND METHODS

Blood flow velocity and pressure were measured in peri-aneurysmal locations by use of an intravascular dual-sensor pressure and Doppler velocity guidewire before and after flow-diverting stent treatment of 4 unruptured cerebral aneurysms. These measurements defined inflow and outflow boundary conditions for computational models. Intra-aneurysmal flow rates, wall shear stress, and wall shear stress gradient were calculated.

RESULTS

Measurements of inflow velocity and outflow pressure were successful in all 4 patients. Computational models incorporating these measurements demonstrated significant reductions in intra-aneurysmal wall shear stress and wall shear stress gradient and a trend in reduced intra-aneurysmal blood flow.

CONCLUSIONS

Integration of intravascular dual-sensor guidewire measurements of blood flow velocity and blood pressure provided patient-specific computational models of cerebral aneurysms. Aneurysm treatment with flow-diverting stents reduces blood flow and hemodynamic shear stress in the aneurysm dome.

Muscle MRI findings in limb girdle muscular dystrophy type 2L

Limb girdle muscular dystrophy type 2L (LGMD2L) is an adult-onset slowly progressive muscular dystrophy associated with recessive mutations in the ANO5 gene. We analysed the muscle MRI pattern in a cohort of 25 LGMD2L patients in order to understand the extent and progression of muscle pathology in LGM2L and assess if muscle MRI might help in the diagnostic work-up of these patients. Our results showed a homogeneous pattern of muscle pathology on muscle MRI, with a predominant involvement of the posterior compartment muscles in both the thighs and calves. The muscles of the anterior compartments in the leg together with the sartorius and gracilis muscles were best preserved, which partially overlaps with patterns observed for other recessive LGMDs. Muscle MRI therefore does not appear to be as useful in the diagnostic work up of LGMD2L as for other neuromuscular diseases, such as Bethlem myopathy or myofibrillar myopathy.

Relationship between osteoarthritis of knee and menopause

AIM

To study the difference in the onset of osteoarthritis (OA) between males and females with respect to age and to note the relationship between OA of the knees and menopause and hysterectomy in females.

MATERIAL AND METHODS

One hundred consecutive patients (50 males and 50 females) were studied for the onset of OA and compared for the statistical difference. In females the relationship between onset of OA and menopause and hysterectomy, if done, was noted.

RESULTS

Fifty eight percent of females had onset of symptoms of OA of knees before 50 years of age as compared to only 20% in males (p < 0.05). Sixty four percent of females with OA of knees had the onset of symptoms either perimenopausally or within five years of natural menopause or hysterectomy.

CONCLUSION

There is a definite early peaking of the incidence of OA of knees in women in the fifth decade of life as compared to males. There is an association between OA of knees and menopause and we suggest correlating it with the levels of sex hormones.

Leprosy: a close mimic in a rheumatology clinic

Cutaneous and neurological manifestations of leprosy are readily diagnosed. However, physicians sometimes fail to recognize that leprosy may present with a rheumatic symptoms. A plethora of rheumatic manifestations are associated with leprosy, particularly with lepra reactions. A diligent examination for skin lesions/nerve involvement may uncover the diagnosis of leprosy in a patient referred for a rheumatological disorder. To highlight the fact that leprosy can mimic several rheumatological disorders, we have discussed a few representative cases seen over the past two years at our rheumatology clinic in a teaching hospital. In all these cases, a diagnosis of leprosy was made when the patient was referred for a rheumatic complaint.

von Willebrand's disease with gastrointestinal telangiectasia

A 30-year old woman presented with recurrent and massive bleeding from gastrointestinal tract. Her coagulation profile revealed von Willebrand's disease and her endoscopic examination showed extensive telangiectasia localized to the gastrointestinal tract. The association of Von Willebrand's Disease and telangiectasia is extremely rare and hence the report.