最先端研究セミナー

講演者：和田　陽一（東北大学 SiRIUS（医学イノベーション研究所）　医学創生研究部　講師）

演題：Galactose Mutarotase Deficiency as the type IV Galactosemia

日時：2025年11月26日（水）　12：00-13：00

開催場所：発生医学研究所1階　カンファレンス室

※ZOOMミーティングのURLはMoodleの「S-HIGO最先端研究セミナーA、B」にてご確認ください。

https://md.kumamoto-u.ac.jp/course/view.php?id=120331

Abstract：

Galactosemia comprises a group of inherited enzyme defects in the Leloir pathway, which metabolizes dietary galactose generated by lactose hydrolysis. Disruption of the Leloir pathway leads to accumulation of galactose and its metabolites. Historically, three enzymatic forms were recognized. In 2019, we identified a fourth form — galactose mutarotase (GALM) deficiency (MIM #618881). GALM (aldose‑1‑epimerase, EC:5.1.3.3) catalyzes the interconversion of α‑ and β‑D‑galactose at the entry point of the Leloir pathway; loss of GALM activity results in accumulation of galactose and its polyol, galactitol, generated from the open‑chain aldehyde. Excess galactitol appears to promote osmotic cataract formation, paralleling other galactosemias. To date, aside from cataracts and transient transaminitis, no additional complications have been consistently documented in GALM deficiency. However, the condition should not be regarded as benign, given clinical experience with irreversible cataracts. A nationwide survey estimated a prevalence of 1 in 181,835, while a separate population‑based estimate 1 in 80,747 derived from genome database analyses and in vitro functional evaluation. Dietary lactose restriction remains the cornerstone of management for galactosemias, including GALM deficiency. Additionally, we have demonstrated that β‑galactosidase supplementation can attenuate elevations in blood galactose in GALM deficiency, supporting its candidacy as an adjunct therapy. This seminar will trace the discovery of GALM deficiency and summarize current understanding, including results of recent research.

担当分野：小児科学講座　中村（5188)