Department of Pediatrics, Division of Endocrinology, Boston Children's Hospital, Boston, MA, USA.
J Pediatr Endocrinol Metab. 2020 Dec 14;34(4):517-520. doi: 10.1515/jpem-2020-0652. Print 2021 Apr 27.
X-linked adrenoleukodystrophy (ALD) affects up to 25% of boys diagnosed with adrenal insufficiency in childhood. Because early identification of these individuals can be lifesaving, all boys with new-onset primary adrenal insufficiency should be tested for ALD with a plasma very long-chain fatty acid (VLCFA) level. While plasma VLCFA is a diagnostic test with high sensitivity and specificity, false-positive results have been reported in individuals on a ketogenic diet.
We present a case of an 11-year-old boy with new-onset primary adrenal insufficiency due to autoimmune adrenalitis who was initially found to have elevated VLCFA levels, suggestive of ALD, that normalized on repeat testing.
As advances in gene therapy and newborn screening for ALD expand, VLCFA testing may increase, and clinicians should be aware that testing during the initial presentation of primary adrenal insufficiency may lead to false-positive results and associated psychosocial distress.
X 连锁肾上腺脑白质营养不良（ALD）影响多达 25%在儿童期被诊断为肾上腺功能不全的男孩。由于早期识别这些个体可以挽救生命，所有新诊断为原发性肾上腺功能不全的男孩都应通过血浆极长链脂肪酸（VLCFA）水平进行 ALD 检测。虽然血浆 VLCFA 是一种具有高灵敏度和特异性的诊断检测方法，但在进行生酮饮食的个体中已报告了假阳性结果。
我们报告了一例 11 岁男孩，因自身免疫性肾上腺炎而出现新诊断的原发性肾上腺功能不全，最初发现 VLCFA 水平升高，提示 ALD，重复检测后恢复正常。
随着 ALD 的基因治疗和新生儿筛查的进展，VLCFA 检测可能会增加，临床医生应该意识到，在原发性肾上腺功能不全的初始表现期间进行检测可能会导致假阳性结果和相关的心理社会困扰。
