Assay of γ-glutamyl transferase (GGT) activity is a widely used test to indicate and monitor liver and biliary tract injury. We observed dominant inheritance of highly elevated plasma GGT levels, designated GGTemia, in two unrelated families. Neither clinical symptoms nor alterations of GGT substrates were associated with GGTemia. A plasma GGT fractions pattern distinguishes this trait from common liver diseases. Heterozygous GGT1 mutations that disrupt the GGT1 transmembrane domain were identified. We establish GGTemia as a benign condition; GGT1 mutation testing can prevent repeated and invasive diagnostic workup in such patients.

中文翻译：

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血浆γ-谷氨酰转移酶高度升高：由 GGT1 跨膜突变引起的性状

γ-谷氨酰转移酶 (GGT) 活性的测定是一种广泛使用的测试，用于指示和监测肝脏和胆道损伤。我们在两个不相关的家族中观察到高度升高的血浆 GGT 水平的显性遗传，称为 GGTemia。GGT 底物的临床症状和改变均与 GGT 血症无关。血浆 GGT 分数模式将此特征与常见肝脏疾病区分开来。鉴定了破坏 GGT1 跨膜结构域的杂合 GGT1 突变。我们将 GGTemia 确定为一种良性病症；GGT1 突变检测可以防止此类患者重复进行侵入性诊断检查。