X-连锁肾上腺脑白质营养不良(X-linked adrenoleukodystrophy,X-ALD)是一种编码过氧化物酶体跨膜蛋白三磷酸腺苷结合盒亚家族D成员1(adenosine 5′-triphosphate binding cassette subfamily D member 1,ABCD1)基因突变的遗传病,其具有多种临床表现,从首发症状到致死性炎性脱髓鞘的进展过程极其快速。因此,识别早期临床症状,早诊断、早治疗能有效阻止该疾病进展。本研究报道1例少见的以“皮肤色素沉着3年”为唯一临床表型的X-ALD患者的实验室检查及影像学特点,并采用高通量测序为患者及其父母进行ABCD1基因测序。实验室检查结果提示患者肾上腺皮质功能减退,血清极长链脂肪酸浓度增高;肾上腺及脑MRI显示未见明显异常信号影。患者基因检测结果显示ABCD1基因外显子1发生c.521A>C半合子突变,其母亲为同位点杂合突变,故诊断为“X-连锁肾上腺脑白质营养不良”。随访过程中,患者肾上腺皮质功能不全症状没有改善,颅脑MRI显示右侧放射冠、左侧顶叶脑白质见少许点状高flair信号影,提示可能出现脑损伤。仅有皮肤表现而无神经系统异常的X-ALD患者极易被忽视,早期诊断并给予早期干预是延缓该疾病进展的重要途径。因此,建议所有的男性儿童患者以皮肤色素沉着为唯一临床表现,继而诊断肾上腺皮质功能减退时,都应该进行基因检测,及早鉴别X-ALD。

X-linked adrenoleukodystrophy (X-ALD) is an inherited disease caused by a mutation in the adenosine 5′-triphosphate binding cassette subfamily D member 1 (ABCD1) gene encoding a peroxisomal transmembrane protein, which has various clinical manifestations and a rapid progression from initial symptoms to fatal inflammatory demyelination. Therefore, identification of early clinical symptoms and further early diagnosis as well as treatment can effectively prevent disease development. In this study, we reported the laboratory and radiographic features in a rare case of X-ALD with 3-year skin hyperpigmentation as the only manifestation. And the ABCD1 gene was sequenced for the patient and his parents by a high-throughput sequencing method. The results of laboratory examination showed adrenocortical hypofunction and increased serum concentrations of very long-chain fatty acids. Brain MRI showed no obvious abnormal signal shadow. A hemizygous mutation of c.521A>C was detected in the ABCD1 gene of the patient, and his mother has the same site heterozygous mutation. Therefore, this patient was diagnosed as “X-linked adrenoleukodystrophy”. During the follow-up, adrenocortical hypothyroidism did not improve, and brain MRI showed few high-FLAIR signals in the white matter of the right radial corona and left parietal lobe, suggesting possible brain injury. X-ALD patients with only skin manifestations but no neurological abnormalities are easily neglected, but early diagnosis and early intervention are important ways to delay the progression of this disease. Therefore, genetic testing for early X-ALD is recommended in all male children patients with skin pigmentation as the sole clinical presentation and subsequent diagnosis of adrenal hypofunction.