Utilization of the 2017 diagnostic criteria for hEDS by the Toronto GoodHope Ehlers–Danlos syndrome clinic: A retrospective review

The new 2017 diagnostic criteria for hypermobile Ehlers–Danlos Syndrome (hEDS) provide a framework for diagnosing hEDS but are more stringent than the previous Villefranche criteria. Our clinical experience at the GoodHope EDS clinic was that the 2017 criteria left many highly symptomatic patients without a diagnosis of hEDS. We conducted a retrospective cohort study to confirm our clinic experience and assess the accuracy of the 2017 diagnostic criteria for hEDS in patients who had a previous hEDS diagnosis based on the Villefranche criteria. Our study found that 15% (n = 20 of 131) of patients with a prior diagnosis of hEDS met the 2017 diagnostic criteria, and many of the traits used to distinguish hEDS were not significantly more frequent in patients who met 2017 criteria versus those who did not. In both groups objective systemic manifestations were found less frequently than subjective systemic manifestations. Beighton score (BS) as assessed by primary care practitioner was found to be higher than assessment by EDS practitioner in 81% (n = 74 of 91) of cases. Generalized joint hypermobility was confirmed in only 46% (n = 51 of 111) of patients who had a previous diagnosis of hEDS. Higher BS did not correlate with increased number of systemic manifestations in our cohort. Common comorbidities of hEDS were found with similar frequency in those who met 2017 criteria and those who did not. Based on our cohort, the 2017 hEDS diagnostic criteria require refinement to improve its diagnostic accuracy.     

Apoptotic cell death in mouse models of GM2 gangliosidosis and observations on human Tay-Sachs and Sandhoff diseases

Tay-Sachs and Sandhoff diseases are autosomal recessive neurodegenerative diseases resulting from the inability to catabolize GM2 ganglioside by beta-hexosaminidase A (Hex A) due to mutations of the alpha subunit (Tay-Sachs disease) or beta subunit (Sandhoff disease) of Hex A. Hex B (beta beta homodimer) is also defective in Sandhoff disease. We previously developed mouse models of both diseases and showed that Hexa-/- (Tay-Sachs) mice remain asymptomatic to at least 1 year of age while Hexb-/- (Sandhoff) mice succumb to a profound neurodegenerative disease by 4-6 months of age. Here we find that neuron death in Hexb-/- mice is associated with apoptosis occurring throughout the CNS, while Hexa-/- mice were minimally involved at the same age. Studies of autopsy samples of brain and spinal cord from human Tay-Sachs and Sandhoff diseases revealed apoptosis in both instances, in keeping with the severe expression of both diseases. We suggest that neuron death is caused by unscheduled apoptosis, implicating accumulated GM2 ganglioside or a derivative in triggering of the apoptotic cascade.      

Functional consequences of ROMK mutants linked to antenatal Bartter's syndrome and implications for treatment

The antenatal variant of Bartter's syndrome is an autosomal recessive kidney disease characterized by polyhydramnios, premature delivery, hypokalemic alkalosis and hypercalciuria. It is genetically heterogeneous, having been linked recently to mutations in an ATP- sensitive, renal outer medullary K+channel, ROMK, and earlier to mutations in the Na-K-2Cl co-transporter, NKCC2. We characterized four of the mutations reported in three heterozygous ROMK variants of antenatal Bartter's and found that each expressed a distinct phenotype in Sf9 cells. One mutation expressed normal function and appears to be an allelic polymorphism. The other three mutations produced channels with significantly reduced K+fluxes. However, the mechanisms in each case were different and reflected abnormalities in phosphorylation, proteolytic processing or protein trafficking. The different mechanisms may be important in the design of appropriate therapy for patients with this disease.      

Cellular basis of an auto-anti-allotypic mechanism for the maintenance of chronic allotype suppression in the rabbit.

Immunocytochemical identification of antibody-forming cells (AFCs) in situ was used to test the hypothesis that the maintenance of chronic allotype suppression in heterozygous rabbits is the result of an autoimmune B-cell-mediated response. Appreciable numbers of B cells with antibody activity directed against the suppressed allotypic determinant were found in spleen and bone marrow sections of all chronically suppressed rabbits examined. Appropriate double-staining was used to determine that such cells were of the non-suppressed allotype. These cells were indistinguishable from anti-allotypic AFCs found in larger numbers in spleens of normal heterozygous rabbits that had been immunized against a heterologous allotypic determinant. Auto-anti-allotypic AFCs were not found in suppressed rabbits less than 8 week old, nor were they found in normal (non-suppressed) heterozygous rabbits or chimeric rabbits formed by the injection of histocompatible but allotype-mismatched lymphoid cells at birth. The findings reported here support the hypothesis that the long-term maintenance of allotype suppression in the rabbit may result from the suppressive activities of autoimmune B cells. It is suggested that the suppression of an allotype during the first few weeks of life could result in a loss of tolerance to a self-determinant. The kinetics of auto-anti-AFC production support this idea in showing that such cells are generated following the decline of the antibody used to induce suppression. The triggering event may be the emergence of B cells expressing the previously suppressed gene product.     

Predictors of sunbathing and sunscreen use in college undergraduates

Sunbathing and sunscreen use, as well as related intentions, attitudes, beliefs, and knowledge, were assessed in 90 Southern Appalachian undergraduates. A large majority (75%) reported sunbathing, with more than half reporting sun lamp use. A slight majority (56.7%) reported some use of sunscreen. Subjects reporting an intention to tan spent more time sunbathing, both outside and under a sun lamp. Individuals reporting a sun protection intention had lighter tans and spent less time sunbathing. Sunbathing was predicted by perceptions of sunbathing as relaxing, while sun lamp use was predicted by more positive views of suntatns. Sunscreen use was predicted by more positive sun protection attitudes and less negative sunscreen attitudes.     

Culture confirmation of cytomegalovirus and herpes simplex virus by direct enzyme-labeled DNA probes and in situ hybridization.

Using probes consisting of horseradish peroxidase (HRP) directly attached to DNA, scrapings or trypsinized cells from 217 adequate clinical samples were cultured and analyzed in 3 blind studies by in situ hybridization for the presence of cytomegalovirus (CMV) and herpes simplex virus (HSV). Sixty samples were judged inadequate due to insufficient cell numbers; however, this problem was significantly decreased during the course of the study. One hundred and eighteen samples were found positive and 70 samples were found negative for CMV. Scrapings of cultured cells from 29 clinical samples revealed 9 samples which were positive and 20 samples which were negative for HSV. Forty-two additional samples, containing either uninfected cells or cells infected with various strains of CMV, were analyzed for the ability of the HRP-DNA CMV probe to detect such isolates. Twenty samples were positive and 22 negative for CMV. No false-negatives or false-positives were observed for either CMV or HSV. In addition to the specificity noted above neither the CMV nor the HSV DNA probe hybridized to potential contaminants found in clinical specimens.     

Degeneration of the intervertebral disks and spondylosis in aging sand rats

Aging sand rats (Psammomys obesus) kept on a standard laboratory diet supplemented by salt bush--their natural source of food--were examined for changes of the vertebral column. From about 6 months of age on, degeneration of the intervertebral disks was noted. The changes increased in severity with increasing age, and from 1 1/2 years of age on, massive multiple disk herniations were seen. Associated with these lesions were spondylosis of "intervertebral" as well as hyperostotic type, and osteoarthrosis of the apophyseal joint. The sand rat seems to be an excellent model for the study of the pathogenesis of spinal diseases associated with the aging process.