Generation and characterization of a human iPSC line and gene-corrected isogenic line derived from a patient with a CELF2 gene mutation.

The identification of neurodevelopmental defects in a patient harboring a heterozygous de novo missense variant (NM_006561.4, c.1517G > A, p.Arg506His) within the CELF2 gene. Here, we describe the establishment of a patient-derived induced pluripotent stem cell (iPSC) line, alongside an isogenic gene-corrected iPSC line, achieved through CRISPR/Cas9 genome editing. These lines exhibit the expression of pluripotency markers, demonstrate differentiation potential into all three germ layers, and maintain a normal karyotype. These iPSC lines serve as valuable tools for investigating the consequences of CELF2 related neurodevelopmental disorders.

A Dermatopathologist's Guide to Troubleshooting Immunohistochemistry--Part 2: Troubleshooting Immunohistochemical Tests in the Laboratory.

Unexpected staining patterns can arise from problems occurring in any of the steps required for IHC, some of which are discussed in part I of this CME series. Whether used to differentiate benign from malignant tumors, identify tumor subtypes, subtypes of hematopoietic malignancies, or identifying targets for therapy, the pathologist must be intimately familiar with the potential pitfalls that are inherent in the IHC methodology to troubleshoot problems in the laboratory, and more importantly, when interpreting immunohistochemical staining, to avoid pitfalls of false-positive or false-negative stains.

A Dermatopathologist's Guide to Troubleshooting Immunohistochemistry Part 1: Methods and Pitfalls.

Immunohistochemistry (IHC) is a method by which specific target antigens can be detected in formalin-fixed paraffin-embedded tissue and involves the use of monoclonal or polyclonal antibodies; visualization of specific tissue antigens is achieved through an enzymatic reaction that transforms a colorless chromogen to a colored one. These enzymes may be attached to the antibody through a protein-ligand method (eg, biotin-avidin or biotin-streptavidin) or through a secondary antibody. Epitopes that are masked by protein linkage during formalin fixation are unmasked using a retrieval system that either uses heat (heat-induced epitope retrieval) or proteolytic enzymes (proteolytic-induced epitope retrieval). Part 1 of this review will focus and elaborate on the available methodologies for IHC testing, common problems inherent to each technique, and how they can be resolved. Part 2 will focus on common problems and artifacts encountered during IHC staining, likely causes, and methods for addressing each problem.