Yusen Qiu1,2, Ling Xin3, Yuyao Wang2, Yanyan Yu1,2, Keji Zou1,2, Qian Zhou1,2, Yunqing Chen1,2, Shuyun Chen1,2, Min Zhu2, Daojun Hong1. 1. Department of Neurology, Peking University People's Hospital, Beijing, China. 2. Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, China. 3. Department of Health, Exercise Science and Recreation Management, University of Mississippi, Oxford, Mississippi, USA.
Abstract
BACKGROUND: Adult adrenomyeloneuropathy (AMN) is caused by mutations in the ABCD1 gene. Some pure AMN patients develop cerebral demyelination late in life. However, hypoplasia and agenesis of the corpus callosum (CC) has never been reported in AMN patients. OBJECTIVE: To describe a new clinical variant of AMN that is possibly caused by a novel ABCD1 gene mutation. METHODS: A total of 10 members in an X-linked inherited family were examined. The age at onset, progression of disability, and clinical manifestations were collected. Blood tests of the index case were conducted in an academic hospital. Cerebral and spinal MRI was performed in 4 affected members using a Siemens 3.0-T or Hitachi 1.0-T MR scanner. Whole-exome sequencing was conducted in the index case, which was subsequently validated by Sanger sequencing in the family. RESULTS: The patients displayed typical degenerative spastic paraparesis and peripheral sensorimotor neuropathy with some intrafamilial variations. In addition to neurological deficits, all male patients displayed alopecia since adolescence. Furthermore, an increase in plasma long-chain fatty acids was observed. Based on these presentations, adult AMN was diagnosed for the patients. Intriguingly, cerebral MRI showed multiple types of hypoplasia and agenesis of the CC including anterior remnant CC agenesis, truncated corpus and splenium, anterior remnant CC agenesis along with thin corpus and splenium. Whole-exome sequencing revealed a nonsense mutation (c.231G>A) which results in a truncated protein product (p.W77X) that might be nonfunctional. No other mutations associated with alopecia or hypoplasia and agenesis of the CC were identified in the exome-sequencing database. CONCLUSION: In addition to the typical symptoms such as spastic myelopathy, cognitive impairment, mixed neuropathy, and alopecia, AMN patients can also display hypoplasia and agenesis of the CC, which was not described in the other AMN patients reported before.
BACKGROUND: Adult adrenomyeloneuropathy (AMN) is caused by mutations in the ABCD1 gene. Some pure AMNpatients develop cerebral demyelination late in life. However, hypoplasia and agenesis of the corpus callosum (CC) has never been reported in AMNpatients. OBJECTIVE: To describe a new clinical variant of AMN that is possibly caused by a novel ABCD1 gene mutation. METHODS: A total of 10 members in an X-linked inherited family were examined. The age at onset, progression of disability, and clinical manifestations were collected. Blood tests of the index case were conducted in an academic hospital. Cerebral and spinal MRI was performed in 4 affected members using a Siemens 3.0-T or Hitachi 1.0-T MR scanner. Whole-exome sequencing was conducted in the index case, which was subsequently validated by Sanger sequencing in the family. RESULTS: The patients displayed typical degenerative spastic paraparesis and peripheral sensorimotor neuropathy with some intrafamilial variations. In addition to neurological deficits, all male patients displayed alopecia since adolescence. Furthermore, an increase in plasma long-chain fatty acids was observed. Based on these presentations, adult AMN was diagnosed for the patients. Intriguingly, cerebral MRI showed multiple types of hypoplasia and agenesis of the CC including anterior remnant CC agenesis, truncated corpus and splenium, anterior remnant CC agenesis along with thin corpus and splenium. Whole-exome sequencing revealed a nonsense mutation (c.231G>A) which results in a truncated protein product (p.W77X) that might be nonfunctional. No other mutations associated with alopecia or hypoplasia and agenesis of the CC were identified in the exome-sequencing database. CONCLUSION: In addition to the typical symptoms such as spastic myelopathy, cognitive impairment, mixed neuropathy, and alopecia, AMNpatients can also display hypoplasia and agenesis of the CC, which was not described in the other AMNpatients reported before.