De Novo PS1 Mutation (Pro436Gln) in a Very Early-Onset Posterior Variant of Alzheimer's Disease Associated with Spasticity: A Case Report.

We report a patient with sporadic Alzheimer's disease with onset in his twenties found to carry the de novo Pro436Gln mutation in the presenilin 1 gene (PS1). Clinical phenotype featured a posterior cortical syndrome with severe visual agnosia and mild limb spasticity with brisk reflexes. Brain MRI and FDG-PET scans revealed severe parieto-occipital atrophy/hypometabolism. Cerebrospinal fluid biomarkers showed a decrease in Aß42 level and Aß42/40 ratio, increased phospho-tau, and normal total tau. Amyloid PET identified a very high burden of amyloid-ß neuritic plaques in the posterior cortex. Similarities between this and two previously reported cases with this variant support that this mutation has a very strong impact on the clinical phenotype and is consistently associated with spasticity.

Positive/retained SDHB immunostaining in renal cell carcinomas associated to germline SDHB-deficiency: case report.

BACKGROUND: According to WHO, succinate dehydrogenase (SDH)-deficient renal cell carcinoma is characterized by negative immunostaining for SDHB, which remains positive in non-tumor tissue despite germline mutations in the SDHB gene. We now report a patient with a SDHB mutation, c.166_170del (p.Pro56Tyrfs*5) who developed renal cell carcinomas with characteristic morphological features of SDH-deficient renal cell carcinoma but had positive SDHB immunostaining. CASE PRESENTATION: Within a 6-year period, the patient developed two different renal cell carcinomas, which had characteristic morphological features of SDH-deficient renal cell carcinoma (uniform cells characteristically displaying eosinophilic granular material intermixed with fewer cells exhibiting clear intracytoplasmic inclusions and bland centered nuclei) but displayed immunohistochemistry for SDHB with a cytoplasmic granular positivity (mitochondrial pattern) in tumor cells. For the second case, this was initially interpreted as positive by IHC, but on review some subtle differences were identified. CONCLUSIONS: SDHB immunostaining may be positive in renal cell carcinoma associated to germline SDHB deficiency which have other typical morphological features. Immunohistochemistry interpretation may be complex.

Consensus document on the implementation of next generation sequencing in the genetic diagnosis of hereditary cancer. / Documento de consenso sobre la implementación de la secuenciación masiva de nueva generación en el diagnóstico genético de la predisposición hereditaria al cáncer.

Genetic diagnosis of hereditary cancer syndromes offers the opportunity to establish more effective predictive and preventive measures for the patient and their families. The ultimate objective is to decrease cancer morbidity and mortality in high genetic risk families. Next Generation Sequencing (NGS) offers an important improvement in the efficiency of genetic diagnosis, allowing an increase in diagnostic yield with a substantial reduction in response times and economic costs. Consequently, the implementation of this new technology is a great opportunity for improvement in the clinical management of affected families. The aim of these guidelines is to establish a framework of useful recommendations for planned and controlled implementation of NGS in the context of hereditary cancer. These will help to consolidate the strengths and opportunities offered by this technology, and minimise the weaknesses and threats which may derive from its use. The recommendations of international societies have been adapted to our environment, taking the Spanish context into account at organisational and juridical levels. Forty-one statements are grouped under six headings: clinical and diagnostic utility, informed consent and genetic counselling pre-test and post-test, validation of analytical procedures, results report, management of information and distinction between research and clinical context. This guide has been developed by the Spanish Association of Human Genetics (AEGH), the Spanish Society of Laboratory Medicine (SEQC-ML) and the Spanish Society of Medical Oncology (SEOM).

Combining targeted panel-based resequencing and copy-number variation analysis for the diagnosis of inherited syndromic retinopathies and associated ciliopathies.

Inherited syndromic retinopathies are a highly heterogeneous group of diseases that involve retinal anomalies and systemic manifestations. They include retinal ciliopathies, other well-defined clinical syndromes presenting with retinal alterations and cases of non-specific multisystemic diseases. The heterogeneity of these conditions makes molecular and clinical characterization of patients challenging in daily clinical practice. We explored the capacity of targeted resequencing and copy-number variation analysis to improve diagnosis of a heterogeneous cohort of 47 patients mainly comprising atypical cases that did not clearly fit a specific clinical diagnosis. Thirty-three likely pathogenic variants were identified in 18 genes (ABCC6, ALMS1, BBS1, BBS2, BBS12, CEP41, CEP290, IFT172, IFT27, MKKS, MYO7A, OTX2, PDZD7, PEX1, RPGRIP1, USH2A, VPS13B, and WDPCP). Molecular findings and additional clinical reassessments made it possible to accurately characterize 14 probands (30% of the total). Notably, clinical refinement of complex phenotypes was achieved in 4 cases, including 2 de novo OTX2-related syndromes, a novel phenotypic association for the ciliary CEP41 gene, and the co-existence of biallelic USH2A variants and a Koolen-de-Vries syndrome-related 17q21.31 microdeletion. We demonstrate that combining next-generation sequencing and CNV analysis is a comprehensive and useful approach to unravel the extensive phenotypic and genotypic complexity of inherited syndromic retinopathies.

A Comprehensive Analysis of Choroideremia: From Genetic Characterization to Clinical Practice.

Choroideremia (CHM) is a rare X-linked disease leading to progressive retinal degeneration resulting in blindness. The disorder is caused by mutations in the CHM gene encoding REP-1 protein, an essential component of the Rab geranylgeranyltransferase (GGTase) complex. In the present study, we evaluated a multi-technique analysis algorithm to describe the mutational spectrum identified in a large cohort of cases and further correlate CHM variants with phenotypic characteristics and biochemical defects of choroideremia patients. Molecular genetic testing led to the characterization of 36 out of 45 unrelated CHM families (80%), allowing the clinical reclassification of four CHM families. Haplotype reconstruction showed independent origins for the recurrent p.Arg293* and p.Lys178Argfs*5 mutations, suggesting the presence of hotspots in CHM, as well as the identification of two different unrelated events involving exon 9 deletion. No certain genotype-phenotype correlation could be established. Furthermore, all the patients´ fibroblasts analyzed presented significantly increased levels of unprenylated Rabs proteins compared to control cells; however, this was not related to the genotype. This research demonstrates the major potential of the algorithm proposed for diagnosis. Our data enhance the importance of establish a differential diagnosis with other retinal dystrophies, supporting the idea of an underestimated prevalence of choroideremia. Moreover, they suggested that the severity of the disorder cannot be exclusively explained by the genotype.