Abstract:
Liver phosphorylase b kinase (PhK) deficiency (glycogen storage disease type IX), one of the most common causes of glycogen storage disease, is caused by mutations in the PHKA2, PHKB, and PHKG2 genes. Presenting symptoms include hepatomegaly, ketotic hypoglycemia, and growth delay. Clinical severity varies widely. Autosomal recessive mutations in the PHKG2 gene, which cause about 10-15% of cases, have been associated with severe symptoms including increased risk of liver cirrhosis in childhood. We have summarized the molecular, biochemical, and clinical findings in five patients, age 5-16 years, diagnosed with liver PhK deficiency caused by PHKG2 gene mutations. We have identified five novel and two previously reported mutations in the PHKG2 gene in these five patients. Clinical severity was variable among these patients. Histopathological studies were performed for four of the patients on liver biopsy samples, all of which showed signs of fibrosis but not cirrhosis. One of the patients (aged 9 years) developed a liver adenoma which later resolved. All patients are currently doing well. Their clinical symptoms have improved with age and treatment. These cases add to the current knowledge of clinical variability in patients with PHKG2 mutations. Long term studies, involving follow-up of these patients into adulthood, are needed.
摘要:
肝磷酸化酶b激酶(PhK)缺乏症(糖原贮积症IX型),糖原贮积病最常见的原因之一,是由PHKA2,PHKB,和PHKG2基因。出现的症状包括肝肿大,酮症性低血糖,增长延迟。临床严重程度差异很大。PHKG2基因的常染色体隐性突变,导致大约10-15%的病例,与严重症状有关,包括儿童期肝硬化风险增加。我们总结了分子,生物化学,以及五名患者的临床发现,年龄5-16岁,诊断为PHKG2基因突变引起的肝脏PhK缺乏。我们已经在这五名患者中鉴定了PHKG2基因中的五个新的和两个先前报道的突变。这些患者的临床严重程度是可变的。对4名患者的肝活检样本进行了组织病理学研究,所有这些都显示出纤维化的迹象,但不是肝硬化。其中一名患者(9岁)发展为肝腺瘤,后来解决。目前所有患者都做得很好。他们的临床症状随着年龄和治疗而改善。这些病例增加了目前对PHKG2突变患者临床变异性的认识。长期研究,包括这些患者成年后的随访,是需要的。