To explore clinical manifestations and mutation types of ABCD1 gene of children with childhood cerebral X-linked adrenoleukodystrophy (CCALD).

In April 2020, a CCALD boy with epilepsy episodes as first symptom who was treated in West China Second University Hospital, Sichuan University was selected as research subject. His clinical data, including medical history, clinical manifestations, laboratory examination and genetic test results, diagnosis and treatment process, etc. were analyzed by retrospectively analysis method. Literature related to research of children with CCALD was searched from Wanfang data knowledge service platform, China National Knowledge Infrastructure, and PubMed, Foreign Medical Literature Retrieval Service (FMRS) and Embase database by taking " X-linked adrenoleukodystrophy" " child" " ABCD1 gene" as the keywords both in Chinese and English. Literature retrieval time was set from January 2011 to December 2021. Clinical manifestations and ABCD1 gene mutation characteristics of CCALD in searched literature were summarized. This study was consistent with the requirements of World Medical Association Declaration of Helsinki revised in 2013.

①He was 12-year-7-month old, and first visited our hospital in April 2020 for " recurrent seizures for 7 years" . His initial symptom was epilepsy, decline in academic performance, impaired vision etc.. His cranial MRI results on admission showed a symmetrical abnormal signal shadow in alba of parietal lobe and temporal lobe and alba near cornu occipitale, involving posterior limbs of bilateral internal capsule, bilateral thalamus, splenium corporis callosi and cerebral peduncle-corticospinal tract. His genetic test showed that exon 1 of ABCD1 gene had c. 589_590del hemizygous frameshift mutation, resulting in amino acid change pL197Dfs*103, and this mutation was inherited from his mother. He was treated with levetiracetam 30 mg/(kg·d) for epilepsy, citicoline for nourishing nerves and rehabilitation training. His treatment effect was not good, and disease was getting worse. As of January 5, 2022, he was still paralyzed in bed, took food through gastric tube, could not communicate normally, and occasionally had myoclonic movements. ②Literature review results: a total of 23 pieces of literature related to CCALD, and 92 children, including 75 different types of ABCD1 gene mutations. The top 2 mutation types of ABCD1 gene were missense mutation (62.7%, 47/75) and frameshift mutation (25.3%, 19/75), and mutations most frequently occurred in exon 1 (38.7%, 29/75).

The clinical manifestations of CCALD are diverse. The initial symptoms include behavioral and cognitive disorders, but some children show severe neurological dysfunctions at the first onset. Typical features of cranial MRI are symmetrical lesions of alba in bilateral parietal and occipital lobes. Missense mutations are the most common mutations in ABCD1 gene, most of which occur in exon 1.