Overlapping cortical malformations in patients with pathogenic variants in GRIN1 and GRIN2B.

BACKGROUND: Malformations of cortical development (MCDs) have been reported in a subset of patients with pathogenic heterozygous variants in GRIN1 or GRIN2B, genes which encode for subunits of the N-methyl-D-aspartate receptor (NMDAR). The aim of this study was to further define the phenotypic spectrum of NMDAR-related MCDs. METHODS: We report the clinical, radiological and molecular features of 7 new patients and review data on 18 previously reported individuals with NMDAR-related MCDs. Neuropathological findings for two individuals with heterozygous variants in GRIN1 are presented. We report the clinical and neuropathological features of one additional individual with homozygous pathogenic variants in GRIN1. RESULTS: Heterozygous variants in GRIN1 and GRIN2B were associated with overlapping severe clinical and imaging features, including global developmental delay, epilepsy, diffuse dysgyria, dysmorphic basal ganglia and hippocampi. Neuropathological examination in two fetuses with heterozygous GRIN1 variants suggests that proliferation as well as radial and tangential neuronal migration are impaired. In addition, we show that neuronal migration is also impaired by homozygous GRIN1 variants in an individual with microcephaly with simplified gyral pattern. CONCLUSION: These findings expand our understanding of the clinical and imaging features of the 'NMDARopathy' spectrum and contribute to our understanding of the likely underlying pathogenic mechanisms leading to MCD in these patients.

Complex Compound Inheritance of Lethal Lung Developmental Disorders Due to Disruption of the TBX-FGF Pathway.

Primary defects in lung branching morphogenesis, resulting in neonatal lethal pulmonary hypoplasias, are incompletely understood. To elucidate the pathogenetics of human lung development, we studied a unique collection of samples obtained from deceased individuals with clinically and histopathologically diagnosed interstitial neonatal lung disorders: acinar dysplasia (n = 14), congenital alveolar dysplasia (n = 2), and other lethal lung hypoplasias (n = 10). We identified rare heterozygous copy-number variant deletions or single-nucleotide variants (SNVs) involving TBX4 (n = 8 and n = 2, respectively) or FGF10 (n = 2 and n = 2, respectively) in 16/26 (61%) individuals. In addition to TBX4, the overlapping ∼2 Mb recurrent and nonrecurrent deletions at 17q23.1q23.2 identified in seven individuals with lung hypoplasia also remove a lung-specific enhancer region. Individuals with coding variants involving either TBX4 or FGF10 also harbored at least one non-coding SNV in the predicted lung-specific enhancer region, which was absent in 13 control individuals with the overlapping deletions but without any structural lung anomalies. The occurrence of rare coding variants involving TBX4 or FGF10 with the putative hypomorphic non-coding SNVs implies a complex compound inheritance of these pulmonary hypoplasias. Moreover, they support the importance of TBX4-FGF10-FGFR2 epithelial-mesenchymal signaling in human lung organogenesis and help to explain the histopathological continuum observed in these rare lethal developmental disorders of the lung.

Understanding the new BRD4-related syndrome: Clinical and genomic delineation with an international cohort study.

BRD4 is part of a multiprotein complex involved in loading the cohesin complex onto DNA, a fundamental process required for cohesin-mediated loop extrusion and formation of Topologically Associating Domains. Pathogenic variations in this complex have been associated with a growing number of syndromes, collectively known as cohesinopathies, the most classic being Cornelia de Lange syndrome. However, no cohort study has been conducted to delineate the clinical and molecular spectrum of BRD4-related disorder. We formed an international collaborative study, and collected 14 new patients, including two fetuses. We performed phenotype and genotype analysis, integrated prenatal findings from fetopathological examinations, phenotypes of pediatric patients and adults. We report the first cohort of patients with BRD4-related disorder and delineate the dysmorphic features at different ages. This work extends the phenotypic spectrum of cohesinopathies and characterize a new clinically relevant and recognizable pattern, distinguishable from the other cohesinopathies.

Change in lentigo maligna score assessed by in vivo reflectance confocal microscopy after 1 month of imiquimod treatment for lentigo maligna management.

BACKGROUND: Treatment of lentigo maligna (LM) is challenging because of the potential functional and esthetic surgical sequelae. Imiquimod has been proposed as a treatment for LM. Reflectance confocal microscopy (RCM) is a noninvasive method for the diagnosis of LM and margin assessment. OBJECTIVES: To compare the overall LM score (LMS) assessed by RCM before and 1 month after the start of imiquimod treatment compared to placebo and to define the immunohistochemical (IHC) profile of responders to imiquimod. METHODS: A controlled randomized study was conducted. Forty patients underwent RCM examination with calculation of the LMS at baseline and after 1 month of treatment. An IHC analysis of excised tissues was performed. RESULTS: The 1-month LMS was significantly lower in patients treated with imiquimod compared to those treated with placebo (P < .001). The criteria in the imiquimod-treated patients that demonstrated significant decrease were nonedged papillae; large, round pagetoid cells; atypical cells at the dermoepidermal junction; and follicular location of atypical cells. IHC analysis showed a higher level of interferon gamma in the resected specimens of patients responding to imiquimod (P = .04). LIMITATIONS: Sample size was small. CONCLUSION: Assessing the LMS by RCM was useful to monitor LM response to imiquimod accurately.

Acanthosis nigricans, hypochondroplasia, and FGFR3 mutations: Findings with five new patients, and a review of the literature.

Early development of extensive acanthosis nigricans (AN) is a key feature in some patients who have hypochondroplasia (HCH) in association with FGFR3 mutations. We here report regarding five new patients with HCH who exhibited AN, and we compare their characteristics to the eight patients previously described in the literature. In these patients, the AN lesions began in childhood, and they were extensive. These lesions were located on the torso, the abdomen, and the face, in addition to the typical skin fold sites. Other skin lesions were frequently reported: café-au-lait macules, melanocytic nevi, lentigines, and seborrheic keratosis. The Lys650Thr mutation was the predominant reported mutation of FGFR3.

High-Density of FcγRIIIA+ (CD16+) Tumor-Associated Neutrophils in Metastases Improves the Therapeutic Response of Cetuximab in Metastatic Colorectal Cancer Patients, Independently of the HLA-E/CD94-NKG2A Axis.

Antibody-dependent cellular cytotoxicity (ADCC) in the anti-tumor effect of cetuximab in metastatic colorectal cancer (mCRC) is only based on the impact of FcγRIIIA (CD16) polymorphisms as predictive of therapeutic response. However, nature, density and therapeutic impact of FcγRIIIA+ (CD16) effector cells in tumor remain poorly documented. Moreover, the inhibition of cetuximab-mediated ADCC induced by NK cells by the engagement of the new inhibitory CD94-NKG2A immune checkpoint has only been demonstrated in vitro. This multicentric study aimed to determine, on paired primary and metastatic tissue samples from a cohort of mCRC patients treated with cetuximab: 1) the nature and density of FcγRIIIA+ (CD16) immune cells, 2) the expression profile of HLA-E/ß2m by tumor cells as well as the density of CD94+ immune cells and 3) their impact on both objective response to cetuximab and survival. We demonstrated that FcγRIIIA+ (CD16) intraepithelial immune cells mainly correspond to tumor-associated neutrophils (TAN), and their high density in metastases was significantly associated with a better response to cetuximab, independently of the expression of the CD94/NKG2A inhibitory immune checkpoint. However, HLA-E/ß2m, preferentially overexpressed in metastases compared with primary tumors and associated with CD94+ tumor infiltrating lymphocytes (TILs), was associated with a poor overall survival. Altogether, these results strongly support the use of bispecific antibodies directed against both EGFR and FcγRIIIA (CD16) in mCRC patients, to boost cetuximab-mediated ADCC in RAS wild-type mCRC patients. The preferential overexpression of HLA-E/ß2m in metastases, associated with CD94+ TILs and responsible for a poor prognosis, provides convincing arguments to inhibit this new immune checkpoint with monalizumab, a humanized anti-NKG2A antibody, in combination with anti- FcγRIIIA/EGFR bispecific antibodies as a promising therapeutic perspective in RAS wild-type mCRC patients.

Medicopsis romeroi nodular subcutaneous infection in a kidney transplant recipient.

Phaeohyphomycosis is a set of fungal infections caused by various dematiaceous fungi such as coelomycetes. These infections can occur either in immunocompetent or immunocompromised patients like solid organ transplants. Here we describe a nodular lesion of the right hallux that occurred in a kidney transplant patient. Microscopic examination of the biopsy revealed fungal hyphae and culture was positive to a grey to black mould that lacked characteristic elements to be identified. Nucleic acid sequencing targeting the internal transcribed spacer of the ribosomal DNA identified this mould as Medicopsis romeroi. The patient benefited of an antifungal therapy with voriconazole associated with surgical excision of the lesion. No relapse of the lesion was observed during a six-month follow-up. In solid organ transplants, phaeohyphomycosis caused by Medicopsis romeroi are very rare with only 12 cases reported. The clinical history should be well assessed since the lesion can appear several years after a cutaneous trauma that happened in a tropical region. Therapy generally combines antifungals with surgical excision of the lesion in order to avoid any relapse or dissemination of the infection.

Prospective evaluation of two screening methods for molecular testing of metastatic melanoma: Diagnostic performance of BRAF V600E immunohistochemistry and of a NRAS-BRAF fully automated real-time PCR-based assay.

Screening for theranostic biomarkers is mandatory for the therapeutic management of cutaneous melanoma. BRAF and NRAS genes must be tested in routine clinical practice. The methods used to identify these alterations must be sensitive to detect mutant alleles in a background of wild type alleles, and specific to identify the correct mutation. They should not require too much material, since in some cases the available samples are small biopsies. Finally, they should also be quick enough to allow a rapid therapeutic management of patients. Sixty five consecutive formalin-fixed paraffin-embedded (FFPE) melanoma samples were prospectively tested for BRAF mutations with the VE1 (anti-BRAF V600E) antibody and for both BRAF and NRAS mutations with the Idylla NRAS-BRAF-EGFR S492R Mutation Assay cartridges. Results were compared to our routine laboratory practice, allele specific amplification and/or Sanger sequencing and discordant cases confirmed by digital PCR. Excluding discordant by-design-mutations, system failures and DNA quantity or quality failures, BRAF IHC demonstrated an overall concordance of 89% for BRAF V600E mutation detection, the Idylla system gave a concordance of 100% for BRAF mutation detection and of 92.1% for NRAS mutation detection when compared to our reference. When discrepancies were observed, all routine results were confirmed by digital PCR. Finally, BRAF IHC positive predictive value (PPV) was of 82% and negative predictive value (NPV) of 92%. The Idylla cartridges showed a PPV and NPV of both 100% for BRAF mutation detection and a PPV and NPV of 100% and 87% respectively, for NRAS mutation detection. In conclusion, BRAF V600E immunohistochemistry is efficient for detecting the V600E mutation, but negative cases should be further evaluated by molecular approaches for other BRAF mutations. Since 3 NRAS mutations have not been detected by the Idylla NRAS-BRAF-EGFR S492R Mutation Assay, these cartridges should not be used as a substitute for traditional molecular methods in the conventional patient therapeutic care process without the expertise needed to have a critical view of the produced results.