Background Requests from researchers for olfactory mucosal biopsies are increasing as a result of advances in the fields of neuroscience and stem cell biology. Published studies report variable rates of success in obtaining true olfactory tissue, often below 50%. In cases where biopsies are not obtained carefully and confirmed through histological techniques, erroneous conclusions are made. Attention to the epithelium alone without submucosal analysis may add to the confusion. A consistent biopsy technique can help rhinologists obtain higher yields of olfactory mucosa. Confirmatory tissue staining analysis assures olfactory mucosa has been obtained thereby strengthening clinical correlations and scientific conclusions. Methods Biopsies of the septum within the anterior olfactory cleft were obtained under endoscopic guidance in an office procedure room using topical local anesthetic (lidocaine). After mucosal incision, a small, cupped, biopsy forceps was used to obtain specimens approximately 2-3 mm in size. Specimens were sectioned and analyzed with immunohistochemistry for presence of olfactory epithelium and/or olfactory fascicles. Results A total of 14 subjects were biopsied in this analysis. Four subjects had biopsies in the operating room (OR). The remaining ten underwent biopsies in the clinic. All biopsies obtained in the OR revealed evidence of olfactory mucosa. A total of eight out of ten (80%) clinic biopsies revealed evidence of olfactory mucosa. No complications were encountered. Conclusion High yields of olfactory mucosa can be obtained safely in an office-based setting. Technique, including attention to the area of biopsy, and confirmatory analysis are important in assuring presence of olfactory tissue.
Purpose: Erythropoietic protoporphyria (EPP), characterized by painful cutaneous photosensitivity, results from pathogenic variants in ferrochelatase (FECH). For 96% of patients, EPP results from coinheriting a rare pathogenic variant in trans of a common hypomorphic variant c.315–48T>C (minor allele frequency 0.05). The estimated prevalence of EPP derived from the number of diagnosed individuals in Europe is 0.00092%, but this may be conservative due to underdiagnosis. No study has estimated EPP prevalence using large genetic datasets. Methods: Disease-associated FECH variants were identified in the UK Biobank, a dataset of 500,953 individuals including 49,960 exome sequences. EPP prevalence was then estimated. The association of FECH variants with EPP-related traits was assessed. Results: Analysis of pathogenic FECH variants in the UK Biobank provides evidence that EPP prevalence is 0.0059% (95% CI: 0.0042%−0.0076%), 1.7–3.0 times more common than previously thought in the UK. In homozygotes for the common c.315–48T>C FECH variant, there was a novel decrement in both erythrocyte mean corpuscular volume (MCV) and hemoglobin. Conclusion: The prevalence of EPP has been underestimated secondary to underdiagnosis. The common c.315–48T>C allele is associated with both MCV and hemoglobin, an association that could be important both for those with and without EPP.
ImportanceErythropoietic protoporphyria (EPP) is a rare and underdiagnosed genetic disease characterized by painful sensitivity to light. A better understanding and characterization of its light-induced cutaneous symptoms may aid in the identification of EPP in patients.ObjectivesTo describe the cutaneous symptoms of erythropoietic protoporphyria (EPP) and to determine if these symptoms are associated with the degree of light sensitivity.Design, Setting, and ParticipantsThis was a cross-sectional study of adolescent and adult (≥15 years) patients with EPP across the US conducted by a single academic hospital via a remotely administered survey, measurements of light sensitivity by light dosimetry and by text message symptom assessments. Data analyses were conducted from November 2020 to April 2022.ExposuresSunlight exposure.Main Outcomes and MeasuresSelf-reported symptoms and association with measured light sensitivity.ResultsThe study sample consisted of 35 patients with EPP (mean [SD] age, 39.1 (15.5) years; 21 [60%] female; 14 [40%] male; 35 [100%] White individuals). The patients’ median [range] skin tone was 3.0 (1.0-8.0), based on self-reporting from 1 (lightest) to 12 (darkest). A total of 24 participants completed the light dosimeter measurements. Phototoxic reactions were characterized by pain (97%; 34 patients), burning (97%; 34), tingling (97%; 34), pruritus (83%; 29), allodynia (89%; 31), improvement of symptoms with cold (89%; 31), achiness (24%; 12), fatigue (46%; 16), mild swelling (83%; 29), severe swelling (63%; 22), erythema (51%; 18), petechiae (40%; 14), skin cracking (43%; 15), scabbing (46%; 16), scarring (66%; 23), and other chronic skin changes (40%; 14). Patients with EPP reported that their hands, feet, and face were most sensitive to light and that their shoulders and legs were least sensitive; 25.7% (9 patient) reported no chronic skin changes, and 5.7% (2 patients) reported never having had any visible symptoms. None of these findings varied with the degree of light sensitivity except that lower overall light sensitivity was associated with lower ranked sensitivity of the neck and arms.Conclusions and RelevanceThe findings of this cross-sectional study suggest that patients with EPP have distinctive cutaneous symptoms that may aid in identification of this underdiagnosed disease. Characteristic EPP symptoms include light-induced cutaneous burning pain and occasional swelling, particularly over the hands, with a prodrome of pruritus and paresthesias. Minimal skin changes or the absence of visible skin changes during reactions to light, including lack of erythema, do not exclude an EPP diagnosis nor suggest low EPP disease burden.
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