眼咽型肌营养不良汉族六家系的临床和遗传学特点

目的 初步总结我国汉族眼咽型肌营养不良(OPMD)患者的临床和多腺苷酸结合蛋白核1(PABPN1)基因改变特点.方法 6个OPMD家系共28例患者,男性13例,女性15例,发病年龄32～70岁,平均发病年龄49.7岁.在可确定首发症状的患者中,以吞咽困难或构音障碍首发的13例、眼睑下垂首发的4例、双下肢无力首发的1例.经过3～20年均出现眼睑下垂、吞咽困难和构音障碍,其中7例出现四肢近端无力.对6例先证者做肌肉活体组织检查,标本进行常规组织病理和电镜检查.对6个家系的先证者以及部分家庭成员进行PABPN1基因检查,并对6例先证者进行单体型分析.结果 6例先证者的肌肉活体组织检查均发现肌纤维直径轻度变异加大伴随肌纤维内镶边空泡形成,4例患者经电镜检查发现OPMD典型的核内栅栏样丝状包涵体.3个家系的PABPN1基因型为(GCG)9,另外3个家系的基因型分别为(GCG)6(GCA)1(GCG)3、(GCG)10和(GCG)8.2个携带(GCG)9突变的家系存在rs2239579(C)-(GCG)9-SNP2622(C)的单倍体型.结论 吞咽异常和眼睑下垂均是我国汉族OPMD患者的首发症状.肌纤维出现镶边空泡以及核内包涵体是我国患者的常见病理改变.PABPN1基因的(GCG)异常扩增和(GCA)插入突变均出现在我国患者,起源具有多源性.携带(GCG)9突变的部分家系可能来自共同祖先.

Phenotypic and genotypic studies in 6 Chinese Han families with oculopharyngeal muscular dystrophy

Objective To explore phenotypes and genotypes in 6 Chinese Han families with oculopharyngeal muscular dystrophy (OPMD).Methods There were 28 OPMD patients in 6 Chinese Han families, aged between 32 and 70 years old.The initial symptom was dysphagia in 13 patients, ptosis in 4 patients,lower limb weakness in 1 patient.Most OPMD patients displayed dysphagia and ptosis in 3-20 years after the initial symptom appeared.Biceps brachii biopsies were made in the 6 OPMD probands.The specimens were examined with histological, histochemical stainings and ultrastructural examination.The exon 1 of PABPN1 gene was sequenced in all probands of OPMD and some of their family members.Haplotype analysis was executed in the 6OPMD probands.Results Mild hypertrophy and hypotrophy of fibers and rimmed vacuoles were found in each probands of OPMD muscle biopsies.Intranuclear palisading filamentous inclusions only appeared in 4OPMD probands.Gene analysis identified (GCG)9 in exon 1 of PA BPN 1 gene was detected in 3OPMD families, while (GCG) 6 (GCA) 1 (GCG) 3, (GCG) 10 and (GCG) 8were in one family respectively.Two families with (GCG) 9 expansion shared a common rs2239579 (C) -(GCG) 9-SNP2622 (C) haplotype.Conclusions Dysphagia and ptosis may be the common initial symptoms in Chinese Han OPMD patients.Rimmed vacuoles and intranuclear inclusions may be the common pathological feature in the muscle fibers.Both (GCG) expansions and (GCA) insertion of PABPN1 gene could be detected in Chinese patients.The genetic heterogeneity and the haplotype of three (GCG)9 families in our patients indicate that OPMD arises from different origin within the Han population.Some families with the same (GCG)9 expansions probably come from a common ancestor.