Eleven Myths on Nail Melanoma

Tuberous sclerosis complex (TSC) is an autosomal dominant hereditary disease with hamartomatous growths in multiple organs due to loss-of-function variants in TSC1 or TSC2. In approximately 15% of patients with clinical TSC, no pathogenic variant can be identified, and low-level mosaicism is suggested to be one of the reasons. Mosaicism is well-known in TSC and challenges the molecular genetic diagnosis. The advent of next-generation sequencing has improved the diagnostics in TSC including in patients with mosaicism. The TSC phenotype varies widely, and mosaic patients with TSC are often considered to have a milder phenotype. Here, the authors describe a patient with mosaic TSC with a 10% variant allele fraction and manifestations in three organ systems (skin, eyes, and kidneys). Furthermore, the authors studied existing literature about phenotypic organ manifestations in patients with mosaic TSC. No clear definition of the phenotype of patients with mosaic TSC could be established, but unilateral angiofibromas and the absence of tubers and a subependymal nodule could indicate mosaicism. The case shows that patients with low-level mosaic TSC can have multiple affected organ systems though still a mild clinical picture.

Powerful use of automated prioritization of candidate variants in genetic hearing loss with extreme etiologic heterogeneity

Variant prioritization of exome sequencing (ES) data for molecular diagnosis of sensorineural hearing loss (SNHL) with extreme etiologic heterogeneity poses a significant challenge. This study used an automated variant prioritization system (“EVIDENCE”) to analyze SNHL patient data and assess its diagnostic accuracy. We performed ES of 263 probands manifesting mild to moderate or higher degrees of SNHL. Candidate variants were classified according to the 2015 American College of Medical Genetics guidelines, and we compared the accuracy, call rates, and efficiency of variant prioritizations performed manually by humans or using EVIDENCE. In our in silico panel, 21 synthetic cases were successfully analyzed by EVIDENCE. In our cohort, the ES diagnostic yield for SNHL by manual analysis was 50.19% (132/263) and 50.95% (134/263) by EVIDENCE. EVIDENCE processed ES data 24-fold faster than humans, and the concordant call rate between humans and EVIDENCE was 97.72% (257/263). Additionally, EVIDENCE outperformed human accuracy, especially at discovering causative variants of rare syndromic deafness, whereas flexible interpretations that required predefined specific genotype–phenotype correlations were possible only by manual prioritization. The automated variant prioritization system remarkably facilitated the molecular diagnosis of hearing loss with high accuracy and efficiency, fostering the popularization of molecular genetic diagnosis of SNHL.

Out-of-Frame Mutations in ACTN2 Last Exon Cause a Dominant Distal Myopathy With Facial Weakness

Background and ObjectivesTo clinically, genetically, and histopathologically characterize patients presenting with an unusual combination of distal myopathy and facial weakness, without involvement of upper limb or shoulder girdle muscles.MethodsTwo families with a novel form of actininopathy were identified. Patients had been followed up over 10 years. Their molecular genetic diagnosis was not clear after extensive investigations, including analysis of candidate genes and FSHD1-related D4Z4 repeats.ResultsPatients shared a similar clinical phenotype and a common pattern of muscle involvement. They presented with a very slowly progressive myopathy involving anterior lower leg and facial muscles. Muscle MRI finding showed complete fat replacement of anterolateral compartment muscles of the lower legs with variable involvement of soleus and gastrocnemius but sparing thigh muscles. Muscle biopsy showed internalized nuclei, myofibrillar disorganization, and rimmed vacuoles. High-throughput sequencing identified in each proband a heterozygous single nucleotide deletion (c.2558del and c.2567del) in the last exon of the ACTN2 gene. The deletions are predicted to lead to a novel but unstructured slightly extended C-terminal amino acid sequence.DiscussionOur findings indicate an unusual form of actininopathy with specific molecular and clinical features. Actininopathy should be considered in the differential diagnosis of distal myopathy combined with facial weakness.

A Comprehensive Analysis of Hungarian MODY Patients—Part II: Glucokinase MODY Is the Most Prevalent Subtype Responsible for about 70% of Confirmed Cases

MODY2 is caused by heterozygous inactivating mutations in the glucokinase (GCK) gene that result in persistent, stable and mild fasting hyperglycaemia (5.6–8.0 mmol/L, glycosylated haemoglobin range of 5.6–7.3%). Patients with GCK mutations usually do not require any drug treatment, except during pregnancy. The GCK gene is considered to be responsible for about 20% of all MODY cases, transcription factors for 67% and other genes for 13% of the cases. Based on our findings, GCK and HNF1A mutations together are responsible for about 90% of the cases in Hungary, this ratio being higher than the 70% reported in the literature. More than 70% of these patients have a mutation in the GCK gene, this means that GCK-MODY is the most prevalent form of MODY in Hungary. In the 91 index patients and their 72 family members examined, we have identified a total of 65 different pathogenic (18) and likely pathogenic (47) GCK mutations of which 28 were novel. In two families, de novo GCK mutations were detected. About 30% of the GCK-MODY patients examined were receiving unnecessary OAD or insulin therapy at the time of requesting their genetic testing, therefore the importance of having a molecular genetic diagnosis can lead to a major improvement in their quality of life.

Clinician's modern approaches to molecular genetic diagnosis of glioblastomas

The article is devoted to the issue of molecular genetic diagnosis of cerebral glioblastomas. Despite significant advances in neurooncology, little progress has been made in prolonging the life of patients with cerebral glioblastoma, and a significant part of the effectiveness of treatment depends on the recognition of two prognostic biomarkers: mutations of the isocitrate dehydrogenase (IDH) promoter and the methylation of the O6-methylguanine methyl transferase (MGMT) promoter. The article summarizes the data of world and domestic clinical studies, allowing to supplement the histological characteristics of primary glioblastomas with genetic markers: the presence of the TERT mutation, EFGR amplification, loss of PTEN function, LOH 10q, and the presence of the BRAF mutation. It should be noted that the amplification of EGFR, causing resistance to apoptotic stimuli and alkylating chemotherapy with Temozolomide, attracts much attention as a therapeutic target. The frequency of occurrence of the TERT mutation is 90% of all tumors of various genesis, most often the TERT mutation is found in oligodendroglioma or primary glioblastoma. Loss of heterozygosity in the region of localization of the PTEN gene is observed in many types of sporadic tumors, including more than 40% of glioblastomas. Mutations in this gene are found in tumors of the brain, endometrium, prostate, kidney, and mammary gland. The presence of a PTEN mutation is a poor prognostic factor. LOH 22q is much more common in secondary glioblastomas (82%) than in primary glioblastomas (41%). Among brain tumors, the BRAF mutation is most common with pleomorphic xanastrocytoma (60-70%).The BRAF V600E mutation was found in epithelioid glioblastoma, which is a rare and aggressive type of glioblastoma, characterized by an unfavorable prognosis (about 6 months) and frequent leptomeningeal spread. Thus, knowledge of the molecular mechanisms of carcinogenesis will enable a personalized approach to treatment with glioblastomas of the brain.

Preimplantation Genetic Testing for Kidney Disease-Related Genes: A Laboratory’s Experience

<b><i>Introduction:</i></b> Recent literature highlights the clinical utility of genetic testing for patients with kidney disease. Genetic testing provides significant benefits for reproductive risk counseling, including the option of in vitro fertilization with preimplantation genetic testing for monogenic disease (PGT-M). PGT-M allows for a significant reduction in risk for a pregnancy affected with the familial disease. We aim to summarize our experience with PGT-M for genes with kidney involvement as either a primary or secondary feature of the disease. <b><i>Methods:</i></b> All PGT-M tests performed by the reference laboratory between September 2010 and July 2020 were reviewed for clinical indication and cases for which the disease tested included a renal component. Each patient referred for PGT-M had an existing molecular genetic diagnosis themselves or in their family. Frequency of each condition, gene, inheritance pattern, and year over year increase in referral cases was analyzed. <b><i>Results:</i></b> In the study cohort, the most common disease targeted was autosomal dominant polycystic kidney disease, caused by pathogenic variants in the <i>PKD1</i> or <i>PKD2</i> genes, which accounted for 16.5% (64/389) of cases. The 5 most common referral indications accounted for 51.9% (202/389) of the cases. Autosomal recessive inheritance accounted for 52.0% (26/50) of conditions for which PGT-M was performed. The number of PGT-M tests performed for conditions that included either primary or secondary kidney disease increased from 5 cases in 2010 to 47 cases in the 2020 study period. <b><i>Discussion/Conclusion:</i></b> These data suggest that the pursuit of PGT-M by couples at risk for passing on conditions with a kidney component is common and has significantly increased since 2010. With this rising trend of patients undergoing PGT-M and the prerequisite of molecular genetic confirmation in the PGT-M process, this study underscores the importance of the reproductive component to a molecular genetic diagnosis for patients with kidney disease, especially as the accessibility of genetic testing and utilization by nephrologists grows.

Dynamics of hygienic and periodontal indices at the stages of implantological treatment

The level of oral hygiene among many patients with implants is insufficient. In the absence of clinical examination and occupational hygiene, there is an averagely frequent development of inflammation in peri-implant tissuesperi-implantitis, which can cause implant disintegration. It is necessary to control hygiene indicators at the different stages of implantation. Objective: to analyze changes in hygiene and periodontal parameters during implant treatment. Materials and methods: At the stages before implantation, during osseointegration and the year after prosthetics on implants, the hygiene indicators and periodontal and microbiota status of 60 patients with dental implants were analyzed. Control methods used include Oral Hygiene Index Green J.C., Vermillion J.R. (OHI-S); gingivitis index Loe H., Silness J. (GI); Muhllemann index modified by Cowell; and PMA index modified by Parma. The level of halitosis was determined using the organoleptic index and the Halimeter instrument. Molecular genetic diagnosis of periodontopathogenic bacteria in the periodontal and peri-implant space was carried out. Results: Hygiene and periodontics after preimplantation tooth restoration, and periodontal deterioration by the time the implants open, then before replacing the temporary prostheses with permanent ones and after three months of functioning of the prostheses on the implants, which necessitates professional oral hygiene before these stages. Conclusion. Occupational hygiene every three months provides a stable adequate level of hygienic and periodontal indicators for users of prostheses on implants, and also reduces the detection of peri-implantitis.