サコタ　モモコ   SAKOTA Momoko   迫田　桃子    所属   医学部 医学科（東京女子医科大学病院）    職種   助教
言語種別	英語
発表タイトル	Challenges in the Histopathologic Diagnosis of Autosomal Dominant Alport Syndrome: A Comparative Genotype-Based Study
会議名	Kidney Week 2025
主催者	American Society of Nephrology
学会区分	国際学会及び海外の学会
発表形式	ポスター掲示
講演区分	一般
発表者・共同発表者	◎Manabe Shun, Seki Momoko, Ushio Yusuke, Makabe Shiho, Kobayashi Shizuka, Ito Naoko, Kataoka Hiroshi, Taneda Sekiko, Hoshino Junichi
発表年月日	2025/11/06
国名	アメリカ合衆国
開催地 （都市, 国名）	Houston, USA
開催期間	2025/11/05～2025/11/09
概要	Background Recent advances have reshaped the understanding of hereditary nephritis with familial hematuria, including Alport syndrome and thin basement membrane disease (TBMD). Alport syndrome is now considered a spectrum: X-linked (XLAS), autosomal recessive (ARAS), female XLAS, and autosomal dominant (ADAS). While severe forms like XLAS (M) and ARAS have defined pathology—such as GBM lamellation and α5 collagen defects—the features of milder forms, especially ADAS, remain unclear. TBMD also overlaps genetically with ADAS, challenging its benign label. These findings highlight the limits of biopsy and the need for genetic testing. Methods We reviewed patients seen from January 2022 to December 2024 who underwent kidney biopsy and genetic testing (COL4A3, COL4A4, COL4A5) for glomerular hematuria with a family history suggestive of hereditary nephritis or TBMD. Clinical data, light microscopy, type IV collagen α2/α5 staining, electron microscopy, and genetic results were evaluated and compared using Fisher’s exact or chi-square test. Results Forty patients (28 female, mean age 49.4 ± 16.1 years) with persistent glomerular hematuria were included. Genetic testing identified 9 XLAS (4 males), 2 ARAS, 17 ADAS, and 12 without pathogenic variants. All underwent kidney biopsy (47 total), including repeats in six. XLAS (M) and ARAS showed form cell infiltration, GBM lamellation, and absent or weakened α5 collagen staining. Female XLAS showed diffuse GBM thinning but no significant differences from Not AS. ADAS showed marked overlap with Not AS in all features, emphasizing the limited value of biopsy alone and the need for genetic testing in suspected ADAS. Conclusion XLAS (M) and ARAS showed characteristic features, including GBM lamellation and reduced or absent α5 collagen staining, aiding diagnosis when combined with clinical and genetic data. In contrast, ADAS showed findings similar to Not AS, underscoring the limited value of pathology alone and the need for genetic testing, particularly in suspected ADAS.