De Goede Christian, Oh Teik, Joseph Jacob, Muntoni Francesco, Sewry Caroline, Phadke Rahul
Department of Paediatric Neurology, Royal Preston Hospital, Preston, United Kingdom.
Department of Radiology, Royal Preston Hospital, Preston, United Kingdom.
Pediatr Neurol. 2016 Jan;54:49-54. doi: 10.1016/j.pediatrneurol.2015.09.018. Epub 2015 Nov 6.
Clinical presentation with motor delay, proximal weakness, and learning difficulties raise the possibility of a dystrophinopathy, dystroglycanopathy, or myotonic dystrophy. This differential should also include the more recently described choline kinase beta-related muscular dystrophy. This condition is typically characterized by large and abnormally distributed mitochondria on muscle biopsy, which can distinguish this condition from the other muscle conditions in the differential.
We present a boy with choline kinase beta mutations with relatively mild clinical manifestations, including proximal weakness, learning difficulties and elevated creatine kinase. Investigations included muscle magnetic resonance imaging (MRI) with T1 axial sequences through thigh and calves, and needle muscle biopsy of the left vastus lateralis muscle.
MRI showed involvement mainly of the quadriceps femoris, sartorius, and adductor magnus, with selective sparing of the gracilis, hamstrings, and adductor longus and brevis. Muscle biopsy revealed chronic dystrophic features. Oxidative stains demonstrated enlarged mitochondria accentuated peripherally or present diffusely in a few fibres giving a coarsely stippled appearance. A homozygous C.722A>G (p.Asn241Ser) mutation was detected in exon 6 of the CHKB gene.
This selective pattern of skeletal muscle involvement might be helpful for identifying other patients with this condition, even in the absence of diagnostic muscle pathology.
出现运动发育迟缓、近端肌无力和学习困难提示可能患有肌营养不良症、糖基化肌营养不良症或强直性肌营养不良症。鉴别诊断还应包括最近描述的胆碱激酶β相关的肌肉营养不良症。这种疾病的典型特征是肌肉活检时线粒体大且分布异常，这可将其与鉴别诊断中的其他肌肉疾病区分开来。
我们报告一名患有胆碱激酶β突变的男孩，其临床表现相对较轻，包括近端肌无力、学习困难和肌酸激酶升高。检查包括通过大腿和小腿的T1轴位序列进行肌肉磁共振成像（MRI），以及对左侧股外侧肌进行肌肉活检。
MRI显示主要累及股四头肌、缝匠肌和大收肌，而股薄肌、腘绳肌以及长收肌和短收肌选择性未受累。肌肉活检显示慢性营养不良特征。氧化染色显示线粒体增大，在少数肌纤维中呈周边强化或弥漫性分布，呈现出粗糙的点状外观。在CHKB基因的第6外显子中检测到纯合的C.722A>G（p.Asn241Ser）突变。
这种骨骼肌受累的选择性模式可能有助于识别其他患有这种疾病的患者，即使在没有诊断性肌肉病理改变的情况下。
