Genetic complexity of diagnostically unresolved Ehlers-Danlos syndrome.

BACKGROUND: The Ehlers-Danlos syndromes (EDS) are heritable disorders of connective tissue (HDCT), reclassified in the 2017 nosology into 13 subtypes. The genetic basis for hypermobile Ehlers-Danlos syndrome (hEDS) remains unknown. METHODS: Whole exome sequencing (WES) was undertaken on 174 EDS patients recruited from a national diagnostic service for complex EDS and a specialist clinic for hEDS. Patients had already undergone expert phenotyping, laboratory investigation and gene sequencing, but were without a genetic diagnosis. Filtered WES data were reviewed for genes underlying Mendelian disorders and loci reported in EDS linkage, transcriptome and genome-wide association studies (GWAS). A genetic burden analysis (Minor Allele Frequency (MAF) <0.05) incorporating 248 Avon Longitudinal Study of Parents and Children (ALSPAC) controls sequenced as part of the UK10K study was undertaken using TASER methodology. RESULTS: Heterozygous pathogenic (P) or likely pathogenic (LP) variants were identified in known EDS and Loeys-Dietz (LDS) genes. Multiple variants of uncertain significance where segregation and functional analysis may enable reclassification were found in genes associated with EDS, LDS, heritable thoracic aortic disease (HTAD), Mendelian disorders with EDS symptomatology and syndromes with EDS-like features. Genetic burden analysis revealed a number of novel loci, although none reached the threshold for genome-wide significance. Variants with biological plausibility were found in genes and pathways not currently associated with EDS or HTAD. CONCLUSIONS: We demonstrate the clinical utility of large panel-based sequencing and WES for patients with complex EDS in distinguishing rare EDS subtypes, LDS and related syndromes. Although many of the P and LP variants reported in this cohort would be identified with current panel testing, they were not at the time of this study, highlighting the use of extended panels and WES as a clinical tool for complex EDS. Our results are consistent with the complex genetic architecture of EDS and suggest a number of novel hEDS and HTAD candidate genes and pathways.

Targeted next-generation sequencing makes new molecular diagnoses and expands genotype-phenotype relationship in Ehlers-Danlos syndrome.

PURPOSE: Ehlers-Danlos syndrome (EDS) comprises a group of overlapping hereditary disorders of connective tissue with significant morbidity and mortality, including major vascular complications. We sought to identify the diagnostic utility of a next-generation sequencing (NGS) panel in a mixed EDS cohort. METHODS: We developed and applied PCR-based NGS assays for targeted, unbiased sequencing of 12 collagen and aortopathy genes to a cohort of 177 unrelated EDS patients. Variants were scored blind to previous genetic testing and then compared with results of previous Sanger sequencing. RESULTS: Twenty-eight pathogenic variants in COL5A1/2, COL3A1, FBN1, and COL1A1 and four likely pathogenic variants in COL1A1, TGFBR1/2, and SMAD3 were identified by the NGS assays. These included all previously detected single-nucleotide and other short pathogenic variants in these genes, and seven newly detected pathogenic or likely pathogenic variants leading to clinically significant diagnostic revisions. Twenty-two variants of uncertain significance were identified, seven of which were in aortopathy genes and required clinical follow-up. CONCLUSION: Unbiased NGS-based sequencing made new molecular diagnoses outside the expected EDS genotype-phenotype relationship and identified previously undetected clinically actionable variants in aortopathy susceptibility genes. These data may be of value in guiding future clinical pathways for genetic diagnosis in EDS.Genet Med 18 11, 1119-1127.

Misleading thyroid function tests in congenital dysfibrinogenemia.

The presence of latent fibrin clots is a recognised pre-analytical factor that causes inaccurate immunoassay results. This report details a case of a patient with Graves' disease and congenital dysfibrinogenemia (CD) that had serum thyroid function test results (TFTs) that were not in keeping with clinical signs or symptoms. Analysis of plasma samples taken from the patient was shown to provide more accurate results than those obtained using serum samples. Further cases of patients with CD, all sharing the same genetic mutation of fibrinogen, and discordant TFTs are described, where TFTs measurement in serum samples proved to be unreliable. Despite evidence of fibrin effecting immunoassays, this is the first report of its kind linking CD to erroneous immunoassay results. The mechanism is postulated to be related to atypical forms of fibrinogen resulting in latent fibrin in serum samples blocking the antigen binding site and leading to incorrect results. Congenital dysfibrinogenemia is asymptomatic in most patients and therefore abnormal, albeit inaccurate, TFTs may be the first finding. Recognition of CD as a cause of discordant results is important when interpreting TFTs to avoid unnecessary investigations and inappropriate clinical interventions to those with the disorder and potentially identify undiagnosed cases.

Small dense low-density lipoprotein: Analytical review.

BACKGROUND: The causal relationship between low-density lipoprotein (LDL) and atherosclerotic cardiovascular disease (CVD) has been firmly substantiated. LDL consists of a heterogeneous group of particles with different physicochemical and metabolic properties. Among them, small dense LDL (sdLDL) particles are considered an emerging CVD risk factor and a promising CVD risk biomarker. This paper reviews published analytical and calculation-based methods for sdLDL determination in plasma, present their principles, strengths, and weaknesses, and examine the challenges arising from method comparison. METHODS: A literature survey was conducted using the PubMed database. Subject headings and keywords facilitated the search strategy. Titles and abstracts were initially assessed, and the full-text article of the pre-selected ones was reviewed. RESULTS: A range of methods is currently available for the analysis of LDL subfractions and the measurement of sdLDL particle size, number, and cholesterol concentration. Ultracentrifugation (UC), vertical auto profile, gradient gel electrophoresis (GGE), nuclear magnetic resonance (NMR) spectroscopy, high-performance liquid chromatography, ion mobility analysis, and a homogeneous assay are the most prevalent. To date, there is no "gold standard". UC and GGE are the most established techniques, albeit significantly sophisticated. NMR and the homogeneous assay are options with potential clinical use as they yield results rapidly and can be high-throughput. None of the proposed equations for the calculated sdLDL determination has been sufficiently validated to serve as a clinical tool. CONCLUSIONS: Many analytical procedures have been developed for the study of sdLDL particles. Their use remains largely restricted to research laboratories since their analytical and clinical performance, along with the clinical- and cost-effectiveness of sdLDL determination have not been fully established.

A comparative study of visual function of young myopic adults wearing contact lenses vs. spectacles.

PURPOSE: To evaluate the impact of contact lenses wear vs. spectacles wear on visual function of young adults with mild to moderate myopia. METHODS: 57 students (27 male and 30 female) with a mean age of 23 years old participated in the study. Their mean best corrected visual acuity was 10/10 binocularly, all suffered from mild to moderate myopia (-3.75 sph/SD 1.25 sph) and they were both contact lenses and spectacles wearers. The VF-14 questionnaire was administered to assess the contact lenses wear vs. spectacles wear impact score on general daily living among the young individuals. It was used translated in Greek after following the 'translation-back translation' procedure. RESULTS: The mean VF-14 score among spectacles and contact lenses wearers was 100 and 86.78 (SD 4.08) respectively. Although there was a significant difference between the two groups (p<0.05), both scores were related to a satisfactory functional vision for daily living. The contact lenses wearers were facing difficulty especially while driving at night, seeing steps, as well as doing fine handwork (i.e. sewing, knitting or carpentry). CONCLUSIONS: The use of both spectacles and contact lenses provides satisfactory visual functioning for daily activities in young individuals suffering from mild to moderate myopia. However, there is a spectacles' wear superiority in personal satisfaction when compared to contact lenses.

Unilateral optic disc edema in a paediatric patient: diagnostic dilemmas and management.

Introduction. We report a case of unilateral optic disc edema in a paediatric patient and discuss the concerns involved in diagnosis and management of similar cases. Materials and Methods. Female aged 10 years was referred to our clinic due to progressive visual loss of the LE over a few days. Her visual acuities (VA) were RE 10/10, LE 3/10, and she had a relative afferent pupillary defect and decreased colour vision in her LE and normal and painless eye movements. Fundoscopy showed a remarkably swollen disc of the LE, and visual field (VF) examination revealed enlargement of the blind spot and presence of horizontal inferior papillomacular scotoma. Neurological examination, CT of brain and orbits and blood tests were normal. Visual evoked potentials revealed an obstacle in the myelin substance before the optic chiasma of the LE. Results. The patient was treated with intravenous methylprednoslone for 3 days and with oral methylprednizole for 15 days in progressively diminished daily doses. This led to gradual improvement of VA, colour vision, and visual field and resolution of optic disc oedema. Discussion. Concerns that have to be taken into account regarding diagnosis and management of similar cases are related to lumbar puncture indications, treatment with corticosteroids, and appropriate followup.