Primary familial brain calcification linked to deletion of 5' noncoding region of SLC20A2

OBJECTIVES

Primary familial brain calcification (PFBC) is a rare neurological disease often inherited as a dominant trait. Mutations in four genes (SLC20A2, PDGFB, PDGFRB, and XPR1) have been reported in patients with PFBC. Of these, point mutations or small deletions in SLC20A2 are most common. Thus far, only one large deletion covering entire SLC20A2 and several smaller, exonic deletions of SLC20A2 have been reported. The aim of this study was to identify the causative gene defect in a Finnish PFBC family with three affected patients.

MATERIALS AND METHODS

A Finnish family with three PFBC patients and five unaffected subjects was studied. Sanger sequencing was used to exclude mutations in the coding and splice site regions of SLC20A2, PDGFRB, and PDGFB. Whole-exome (WES) and whole-genome sequencing (WGS) were performed to identify the causative mutation. A SNP array was used in segregation analysis.

RESULTS

Copy number analysis of the WGS data revealed a heterozygous deletion of ~578 kb on chromosome 8. The deletion removes the 5' UTR region, the noncoding exon 1 and the putative promoter region of SLC20A2 as well as the coding regions of six other genes.

CONCLUSIONS

Our results support haploinsufficiency of SLC20A2 as a pathogenetic mechanism in PFBC. Analysis of copy number variations (CNVs) is emerging as a crucial step in the molecular genetic diagnostics of PFBC, and it should not be limited to coding regions, as causative variants may reside in the noncoding parts of known disease-associated genes.

A recognizable type of syndromic short stature with arthrogryposis caused by bi-allelic SEMA3A loss-of-function variants

The semaphorins constitute a large family of secreted and membrane-associated proteins that regulate many developmental processes, including neural circuit assembly, bone formation and angiogenesis. Recently, bi-allelic loss-of-function variants in SEMA3A (semaphorin 3A) were identified in a single patient with a particular pattern of multiple congenital anomalies (MCA). Using homozygosity mapping combined with exome sequencing, we identified a homozygous SEMA3A variant causing a premature stop codon in an 8 year old boy with the same pattern of MCA. The phenotype of these patients is characterized by postnatal short stature, skeletal anomalies of the thorax, a minor congenital heart or vascular defect, camptodactyly, micropenis, and variable additional anomalies. Motor development is delayed in both patients, and intellectual development is delayed in one patient. Our observation of a second case supports the notion that bi-allelic mutations in SEMA3A cause an autosomal recessive type of syndromic short stature.

Assessment of practical tasks in the Phantom course of Conservative Dentistry by pre-defined criteria: a comparison between self-assessment by students and assessment by instructors

INTRODUCTION

Assessment of practical skills in undergraduate dental education has difficulties, including a lack of transparency/objectivity in student evaluations. This prospective study investigated whether agreement between student- and faculty-based assessments increased when students were trained to use the assessment criteria.

MATERIALS AND METHODS

Assessment criteria were available for 6 tasks in the Phantom course of Conservative Dentistry: Class II cavity preparation, composite restoration, gold and ceramic partial crown preparation, trepanation and access cavity preparation, and root canal filling. Forty-two students were allocated to three different assessment training groups. Students' self-assessments of practical tests were compared with instructors' assessments, depending on training intensity and task type (Pearson's rho, ANOVA, Tukey's post hoc test, Kruskal-Wallis test). Students/instructors were questioned regarding benefits/drawbacks of the criteria.

RESULTS

Student self-assessments showed either consent (24.2%), overestimation (31%) or underestimation (44.8%). Gender differences were negligible. Regarding passing/failing grades, more intensive training yielded significantly increased agreement only for preparation of gold partial crowns (rho = +0.313, P = 0.044). Ratings exhibited significant differences amongst tasks (P = 0.002), for example, trepanation assessment had significantly lower differences than gold or ceramic preparation assessments. These discrepancies decreased with increased training. Students consistently reported benefitting most from learning the criteria for gold preparations, followed by composite and ceramic preparations. They also reported that learning the criteria was beneficial for knowledge transfer/feedback. Instructors rated the criteria as helpful for task evaluation and feedback efficiency.

CONCLUSIONS

Pre-defined assessment criteria may increase consistency between student self-assessment and instructor assessment depending on the task, improving transparency and feedback in dental education.

Assessment of practical tasks in the Phantom course of Conservative Dentistry by pre-defined criteria: a comparison between self-assessment by students and assessment by instructors

INTRODUCTION

Assessment of practical skills in undergraduate dental education has difficulties, including a lack of transparency/objectivity in student evaluations. This prospective study investigated whether agreement between student- and faculty-based assessments increased when students were trained to use the assessment criteria.

MATERIALS AND METHODS

Assessment criteria were available for 6 tasks in the Phantom course of Conservative Dentistry: Class II cavity preparation, composite restoration, gold and ceramic partial crown preparation, trepanation and access cavity preparation, and root canal filling. Forty-two students were allocated to three different assessment training groups. Students' self-assessments of practical tests were compared with instructors' assessments, depending on training intensity and task type (Pearson's rho, ANOVA, Tukey's post hoc test, Kruskal-Wallis test). Students/instructors were questioned regarding benefits/drawbacks of the criteria.

RESULTS

Student self-assessments showed either consent (24.2%), overestimation (31%) or underestimation (44.8%). Gender differences were negligible. Regarding passing/failing grades, more intensive training yielded significantly increased agreement only for preparation of gold partial crowns (rho = +0.313, P = 0.044). Ratings exhibited significant differences amongst tasks (P = 0.002), for example, trepanation assessment had significantly lower differences than gold or ceramic preparation assessments. These discrepancies decreased with increased training. Students consistently reported benefitting most from learning the criteria for gold preparations, followed by composite and ceramic preparations. They also reported that learning the criteria was beneficial for knowledge transfer/feedback. Instructors rated the criteria as helpful for task evaluation and feedback efficiency.

CONCLUSIONS

Pre-defined assessment criteria may increase consistency between student self-assessment and instructor assessment depending on the task, improving transparency and feedback in dental education.

Ehlers-Danlos syndrome related to FKBP14 mutations: detailed cutaneous phenotype

In 2012, a new Ehlers-Danlos (ED) variant, characterized by severe progressive kyphoscoliosis, neonatal myopathy and hearing loss, with normal urinary lysylpyridinoline to hydroxylysylpyridinoline ratio and most often a recurrent homozygous mutation in the FKBP14 gene, was reported. Because one of the major affected tissues in ED syndrome is the skin, recognition of the cutaneous features of this newly recognized EDS variant is important. We describe the cutaneous phenotype of an adolescent girl harbouring the recurrent homozygous FKBP14 mutation. Distinctive features included molluscoid pseudotumours and multiple isolated comedones. Molluscoid pseudotumours are a characteristic finding in patients with the classic ED variant, but are rarely reported in other variants. We discuss the cutaneous phenotype of FKBP14-deficient EDS and compare it with other kyphoscoliotic variants.

Correlation of FMISO simulations with pimonidazole-stained tumor xenografts: A question of O2 consumption?

PURPOSE

To compare a dedicated simulation model for hypoxia PET against tumor microsections stained for different parameters of the tumor microenvironment. The model can readily be adapted to a variety of conditions, such as different human head and neck squamous cell carcinoma (HNSCC) xenograft tumors.

METHODS

Nine different HNSCC tumor models were transplanted subcutaneously into nude mice. Tumors were excised and immunoflourescently labeled with pimonidazole, Hoechst 33342, and CD31, providing information on hypoxia, perfusion, and vessel distribution, respectively. Hoechst and CD31 images were used to generate maps of perfused blood vessels on which tissue oxygenation and the accumulation of the hypoxia tracer FMISO were mathematically simulated. The model includes a Michaelis-Menten relation to describe the oxygen consumption inside tissue. The maximum oxygen consumption rate M0 was chosen as the parameter for a tumor-specific optimization as it strongly influences tracer distribution. M0 was optimized on each tumor slice to reach optimum correlations between FMISO concentration 4 h postinjection and pimonidazole staining intensity.

RESULTS

After optimization, high pixel-based correlations up to R(2) = 0.85 were found for individual tissue sections. Experimental pimonidazole images and FMISO simulations showed good visual agreement, confirming the validity of the approach. Median correlations per tumor model varied significantly (p < 0.05), with R(2) ranging from 0.20 to 0.54. The optimum maximum oxygen consumption rate M0 differed significantly (p < 0.05) between tumor models, ranging from 2.4 to 5.2 mm Hg/s.

CONCLUSIONS

It is feasible to simulate FMISO distributions that match the pimonidazole retention patterns observed in vivo. Good agreement was obtained for multiple tumor models by optimizing the oxygen consumption rate, M0, whose optimum value differed significantly between tumor models.

Autologous chondrocyte implantation (ACI) for cartilage defects of the knee: A guideline by the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU)

BACKGROUND

Autologous chondrocyte implantation (ACI) is an established and well-accepted procedure for the treatment of localised full-thickness cartilage defects of the knee.

METHODS

The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning therapeutic consequences of primary cartilage lesions and the suitable indication for ACI.

RESULTS

Based on best available scientific evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than three to four square centimetres; in the case of young and active sports patients at 2.5cm(2), while advanced degenerative joint disease needs to be considered as the most important contraindication.

CONCLUSION

The present review gives a concise overview on important scientific background and the results of clinical studies and discusses the advantages and disadvantages of ACI.

LEVEL OF EVIDENCE

Non-systematic Review.