面肩肱型肌营养不良症的基因诊断

目的 对中国人面肩肱型肌营养不良症进行基因诊断。方法 用EcoRI以及EcoRI/BlnI消化基因组DNA,0.6%琼脂糖凝胶电泳,P13E11探针进行Southern印迹杂交。结果 患者所得EcoRI BlnI/P13E11DNA片段长度在15-33kb之间,而正常对照在41kb以上,发现两个症状前患者。结论 以P13E11探针通过Southern印迹杂交探测EcoRi/BlnI双酶消化的基因组DNA可对中国人绝大部分面肩肱型肌营养不良症进行基因诊断,并可进行症状前诊断。     

面肩肱型肌营养不良症基因诊断

目的 观察面肩肱型肌营养不良症(facioscapulohumeral muscular dystrophy，FSHD)患者p13E—11标记的4q35 EcoR Ⅰ／B1n Ⅰ片段分子量变化特点，对FSHD进行基因诊断。方法 提取基因组DNA，EcoR Ⅰ／B1n Ⅰ双酶切后进行脉冲凝胶电泳，用同位素标记的探针p13E—11进行Southern印迹，以小于38kb为诊断FSHD标准，观察4q35 EcoR Ⅰ／B1n Ⅰ片段分子量大小的分布。结果 FSHD组26例患者中，20例4q35 EcoR Ⅰ／B1n Ⅰ片段小于38kb，基因诊断阳性率为76．92％。FSHD亲属组12例，其中两例该片段小于38kb。对照组21人，该片段均大于38kb。结论 以小于38kb为诊断标准较满意，FSHD基因诊断阳性率与文献基本吻合。     

面肩肱型肌营养不良症的分子遗传学研究进展

面肩肱型肌营养不良症（factoscapulohumeral muscular dystrophy,FSHD)呈常染色体显性遗传。大多数致病基因定位于4q35,存在遗传异质性。发现与FSHD相关的DNA重组,即4q35上3．3kb串联重复单位呈不同拷贝数缺失。以p13E-11为探针检测EcoR I/Bln I双重消化的DNA片段,FSHD患者的消化片段通常小于正常人,从而进行有效的分子诊断。由于FSHD基因尚未鉴定与分子,FSHD的确切发病机理仍未阐明,提出有位置效应变异假说等。目前有一候选基因FRG1。与FSHD相关的DNA重组片段的大小与FSHD临床表型之间显著相关,可较好地解释FSHD患者广泛的临床变异性。     

The facioscapulohumeral muscular dystrophy (FSHD1) gene affects males more severely and more frequently than females

We investigated 52 families of patients with facioscapulohumeral muscular dystrophy (FSHD1), including 172 patients (104 males and 68 females). Among 273 DNA samples which were analyzed with probe p13E-11, 131 (67 males and 64 females) were shown to carry an EcoRI fragment smaller than 35 kb; 114 among them were examined clinically and neurologically. Results of the present investigation showed that: a) there is no molecular evidence for autosomal or X-linked recessive inheritance of FSHD1; b) an excess of affected males, which is explained by a significantly greater proportion of females than males among asymptomatic cases and a significantly greater proportion of affected sons than daughters observed in the offspring of asymptomatic mothers; c) the penetrance of the FSHD1 gene until age 30 was estimated as 83% for both sexes but was significantly greater for males (95%) than for females (69%); d) new mutations occur significantly more frequently in females than males among somatic/germinal mosaic cases; and e) severely affected cases originated more often through new mutations or were transmitted through maternal than through paternal lines including somatic/germinal mothers. These observations have important implications for understanding the molecular mechanisms responsible for FSHD1 and for genetic and prognostic counseling according to the gender of the affected patient. Am. J. Med. Genet. 77:155–161, 1998. © 1998 Wiley-Liss, Inc.     

上海人群面肩肱型肌营养不良症相关位点的D4Z4多态性

目的 对上海人群4p35位点D4Z4重复序列进行研究，分析D4Z4的多态性。方法 191名正常上海人的基因组DNA经EooR I/Bln I双酶水解后，应用脉冲场凝胶电泳及Southem印迹测定其染色体4p35位点的D4Z4片段长度，并对短的D4Z4片段Kpn I酶进行部分酶切以计数其D4Z4串联重复序列数。结果 在191名正常上海人群中，有17人（占8.9％）携带短的D4Z4片段，其长度在22－34kb之间；其中16人携带的短D4Z4片段位于4q35位点，1人携带的短D4Z4片段为4q35→10q26。结论 面肩肱型肌营养不良症的发病虽与4q35位点D4Z4片段的串联重复序列数减少有关，但上海人群中携带4q35位点短的D4Z4片段个体的比例明显高于西方人群，提示其他因素可能也参与面肩肱型肌营养不良症的发病。     

一个常染色体显性遗传Emery-Dreifuss型肌营养不良家系的基因突变分析

目的 探讨一个常染色体显性遗传Emery-Dreifuss型肌营养不良(Emery-Dreifuss muscular dystrophy,EDMD)家系的临床、病理及遗传学特点.方法 收集家系中2例患者(先证者及女儿)的临床资料及骨骼肌标本,行组织化学染色病理分析;收集先证者及家系成员(3代7人)血液DNA标本,采用聚合酶链反应和DNA直接测序方法 对LMNA基因进行突变检测;明确基因变异位点后对家系行单倍型分析.结果 先证者具有典型的EDMD临床表现:关节挛缩、进行性加重的肌无力和肌萎缩、心脏传导异常;骨骼肌活检病理示肌源性合并轻度神经源性改变;2例患者LMNA基因第9外显子发现杂合错义突变1583(C→G)(T528R),表型正常的其他家系成员未发现该突变;单倍型分析显示先证者及女儿具有相同的致病单倍型.结论 报道了中国人常染色体显性遗传EDMD患者的表现型及基因型.     

A unique library of myogenic cells from facioscapulohumeral muscular dystrophy subjects and unaffected relatives: family, disease and cell function

To explore possible mechanisms of pathology in facioscapulohumeral muscular dystrophy (FSHD), we generated a novel library of myogenic cells composed of paired cultures derived from FSHD subjects and unaffected first-degree relatives. We prepared cells from biopsies of both biceps and deltoid muscles obtained from each of 10 FSHD and 9 unaffected donors. We used this new collection to determine how family background and disease affected patterns of growth and differentiation, expression of a panel of candidate, and muscle-specific genes, and responses to exogenous stressors. We found that FSHD and unaffected cells had, on average, indistinguishable patterns of differentiation, gene expression, and dose-response curves to staurosporine, paraquat, hydrogen peroxide, and glutathione depletion. Differentiated FSHD and unaffected cultures were both more sensitive to glutathione depletion than proliferating cultures, but showed similar responses to paraquat, staurosporine, and peroxide. For stress responses, the sample size was sufficient to detect a 10% change in effect at the observed variability with a power of >99%. In contrast, for each of these properties, we found significant differences among cells from different cohorts, and these differences were independent of disease status, gender, or muscle biopsied. Thus, though none of the properties we examined could be used to reliably distinguish between FSHD and unaffected cells, family of origin was an important contributor to gene-expression patterns and stressor responses in cultures of both FSHD and unaffected myogenic cells.     

Facioscapulohumeral muscular dystrophy: epidemiological and molecular study in a north-east Italian population sample

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant disease associated with a partial deletion on chromosome 4q35. Few relevant investigations have been reported on its epidemiology and were essentially based on clinical diagnosis, having been performed before recognition of the molecular mutation. We report an epidemiological survey on FSHD patients, in which the diagnosis was obtained by combined clinical and molecular evaluation. The survey concerned the north-east Italian province of Padova, an area of 871,190 inhabitants (1 January 2004). We identified 40 patients affected by FSHD based on clinical diagnosis. In 33 of them, the EcoRI fragment size in the 4q35 region ranged from 14 to 35 kb. Four other patients belonging to the same family harbored a 38-kb fragment. In these four cases, the relationship between the borderline deletion with the mild FSHD phenotype was corroborated by additional haplotype reconstruction and segregation analysis. Interestingly, the same mild facial-sparing clinical pattern was apparent only in one other patient with an EcoRI fragment of 32 kb, suggesting that this unusual FSHD phenotype may be due to very small 4q35 deletions. On the whole, estimating a prevalence rate of 44 × 10⁻⁶, our survey confirmed FSHD as one of the most frequent neuromuscular disorders in Western populations.     

A study of possible heterogeneity in Duchenne muscular dystrophy

One possible explanation for the apparently high birth incidence of Duchenne muscular dystrophy (DMD), a lethal X-linked disorder, is genetic heterogeneity. As a first step in possibly demonstrating genetic heterogeneity, affected boys were sub-divided into those with and without severe mental handicap. In those with severe mental handicap, ages at onset and of becoming confined to a wheelchair were later, the fall in SCK level with age was less marked, and the urinary excretion of certain aminoacids was greater than in affected boys with normal intelligence. Though the number of subjects investigated was relatively small (15 in each group) and further studies are therefore needed, the results suggest that DMD may not be a single disease entity.     

Patent ductus arteriosus and pulmonary valve stenosis in a patient with 18p deletion syndrome

We report on a patient with a partial deletion on the short arm of chromosome 18 (del 18p), who presented with dysmorphic features and delayed developmental milestones as well as with a patent ductus arteriosus (PDA) and pulmonary valve stenosis (PS). Several forms of congenital heart disease (CHD) are found in about 10% of patients with del (18p), but coexisting PDA and PS have not been reported. Del (18p) must be considered in patients with characteristic phenotypic abnormalities and congenital heart disease, including a combination of PDA and PS.     

The effect of motor learning in facioscapulohumeral muscular dystrophy patients

Two models of motor learning (ML) practice (complex and simple) were used to investigate upper limb function in individuals with facioscapulohumeral dystrophy (FSHD). The effect of ML practice was studied by examining changes in the ability to undertake a simulated drinking task. In the complex model, seven FSHD patients and seven age- and gender-matched healthy volunteers were studied. Performance was assessed by measurement of the electromyographic (EMG) activity of the biceps brachii and brachioradialis, elbow joint flexion, shoulder joint flexion and abduction, maximum acceleration at the onset of movement, movement time and reaction time, both before and after a 30-min complex ML task. In the simple model, a second group of six FSHD patients and six age- and gender-matched healthy subjects were studied. The same parameters were measured as for the complex ML task, except that the EMG activity of the triceps and deltoid muscles (anterior part) were measured instead of that of the brachioradialis. In both studies, the FSHD patients showed significantly larger values for all parameters except the flexion of shoulder joint and reaction time, compared with controls before the ML task. In the FSHD group, while the complex ML resulted in decreases in the brachioradialis EMG activity (P < 0.005) and reaction time (P < 0.0001), the simple ML model resulted in significant changes towards the normal value in all parameters measured except shoulder flexion. The change in the measured variables towards normal values indicates that ML may help to improve performance in FSHD. Accepted: 11 July 2000     

克隆缺失连接片段——一种基于PCR技术的缺失型假肥大型肌营养不良症的携带者检测

目的 依据dystrophin基因缺失后断端重接可形成一段变异的DNA序列,提出一种利用缺失连接片段进行缺失型假肥大型肌营养不良症携带者检测的新方法.方法 实验以来自广东省肇庆地区的一个Becker型肌营养不良(Becket muscular dystrophy,BMD)家系为研究对象,其中2例确诊的男性BMD患者,3例待诊的女性携带者,1例待诊的人工流产绒毛.先证者经外显子PCR检测确定第3～5外显子缺失,随后采用PCR步移法在相应内含子设计引物定位断裂点的位点,最后利用靠近断裂点设计的引物直接对家系的6例基因组DNA进行缺失连接片段的PCR扩增和测序.结果 6例基因组DNA均扩增出阳性的产物片段且连接片段的测序序列完全一致,绒毛的性别诊断结果为女性,可以确诊本家系中的3个女性和流产绒毛均为缺失型BMD携带者.结论 作者成功地将整个家系患者和携带者的缺失连接片段进行克隆和测序分析,实现了利用缺失连接片段对缺失型假肥大型肌营养不良症携带者进行准确基因诊断的设想,同时对在产前诊断上的应用前景进行了探讨.     

A girl with 1p36 deletion syndrome and congenital fiber type disproportion myopathy

Chromosome 1p36 deletion syndrome is characterized by hypotonia, moderate to severe developmental and growth retardation, and characteristic craniofacial dysmorphism. Muscle hypotonia and delayed motor development are almost constant features of the syndrome. We report a 4-year-old Japanese girl with 1p36 deletion syndrome whose muscle pathology showed congenital fiber type disproportion (CFTD) myopathy. This is the first case report of 1p36 deletion associated with CFTD. This association may indicate that one of the CFTD loci is located at 1p36. Ski proto-oncogene −/− mice have phenotypes that resemble some of the features observed in patients with 1p36 deletion syndrome. Because fluorescent in situ hybridization analysis revealed that the human SKI gene is deleted in our patient, some genes in 1p36, including SKI proto-oncogene, may be involved in muscle hypotonia and delayed motor development in this syndrome. Received: March 4, 2002 / Accepted: July 7, 2002     

Detection of partial deletion and partial duplication of dystrophin gene in Japanese patients with Duchenne or Becker muscular dystrophy

Summary The dystrophin gene was analyzed in 59 Japanese patients with Duchenne muscular dystrophy (DMD) from 48 unrelated families, including 11 pairs of siblings, and three patients with Becker muscular dystrophy (BMD) from two unrelated families, including one pair of siblings. The relationship between the type of gene abnormality and clinical symptoms was examined. Twenty-seven of 50 (54.0%) unrelated DMD or BMD patients were found to have partial deletions, and five (10%) appeared to have partial duplications in the dystrophin gene. Nine DMD patients, including three pairs of siblings, showed mental retardation, the existence of which was coincident in each pair of siblings, but deletion of an identical exon was not always related to mental retardation in unrelated patients.     

The DNA rearrangement associated with facioscapulohumeral muscular dystrophy involves a heterochromatin-associated repetitive element: Implications for a role of chromatin structure in the pathogenesis of the disease

Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant form of muscular dystrophy. The FSHD locus has been linked to the most distal genetic markers on the long arm of chromosome 4. Recently, a probe was identified that detects anEcoRI fragment length polymorphism which segregates with the disease in most FSHD families. Within theEcoRI fragment lies a tandem array of 3.2 kb repeats. In several familial cases and four independent sporadic FSHD mutations, the variation in size of theEcoRI fragment was due to a decrease in copy number of the 3.2 kb repeats. To gain further insight into the relationship between the tandem array and FSHD, a single 3.2 kb repeat unit was characterized. Fluorescencein situ hybridization (FISH) demonstrates that the 3.2 kb repeat cross-hybridizes to several regions of heterochromatin in the human genome. In addition, DNA sequence analysis of the repeat reveals a region which is highly homologous to a previously identified family of heterochromatic repeats, LSau. FISH on interphase chromosomes demonstrates that the tandem array of 3.2 kb repeats lies within 215 kb of the 4q telomere. Together, these results suggest that the tandem array of 3.2 kb repeats, tightly linked to the FSHD locus, is contained in heterochromatin adjacent to the telomere. In addition, they are consistent with the hypothesis that the gene responsible for FSHD may be subjected to position effect variegation because of its proximity to telomeric heterochromatin.     

Growth hormone deficiency associated in the 18q deletion syndrome

The 18q- syndrome is one of the commonest deletion syndromes. Clinical characteristics are variable but may include: hypotonia, tapered digits, “carp-like” mouth, mental retardation, and hearing impairment. Growth failure (GF; both weight and height <3%) was reported in 80% of affected individuals. We evaluated growth hormone (GH) sufficiency in 5 18q- syndrome patients, 3 of whom had growth failure (<3% weight and height); the remaining 2 had normal growth parameters. Laboratory evaluation of growth included measurement of IGF-1, IGFBP-3, bone ages and GH response to pituitary provocative agents. Three patients failed to produced adequate GH following stimulation testing. Of 3 patients with inadequate GH production, 1 had normal growth (above 3%). Only 1 of 5 patients had normal GH production and normal growth parameters. Our findings to date suggest that GH deficiency is common in individuals with the 18q- syndrome. The pathogenesis of this finding is unknown. We postulate that a gene(s) on 18q is involved in GH production. Am. J. Med. Genet. 69:7–12, 1997. © 1997 Wiley-Liss, Inc.     

De novo variants and recombination at 4q35: Hints for preimplantation genetic testing in facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) has been associated with the deletion of an integral number of 3.3 kb units of the polymorphic D4Z4 repeat array at 4q35. The prenatal identification of this defect can be carried out on chorionic villi or amniocytes, whereas preimplantation genetic testing for monogenic disorders (PGT-M) requires molecular markers linked to the D4Z4 allele of reduced size. In this context the reliability of this association is crucial. To test the informativeness of the nearby polymorphic markers we investigated recombination at 4q35 using the polymorphic markers D4S1523, D4S163 and D4S139 positioned at 0.55, 0.5 and 0.21 Mb proximal to the D4Z4 array respectively. We determined the probability of recombination events to occur in the D4Z4-D4S1523 interval considering 86 subjects belonging to 12 FSHD families and found a recombination frequency of 14% between D4Z4 and D4S1523. Our study also revealed the occurrence of de novo variants and germline mosaicism. These findings highlight the recombinogenic nature of the 4q subtelomere and indicate that caution should be taken when interpreting PGT-M results. It is advisable that a woman who underwent a PGT-M cycle undertakes a prenatal DNA analysis to confirm the size of the D4Z4 alleles carried by the fetus.     

Familial del(18p) syndrome

We report on sibs and their mother, all with del(18p). The propositus, an 11‐month‐old, had developmental delay, round face, hypertelorism, large ears, broad nasal bridge, upturned nostrils, micrognathia, a high palate, redundant skin around the neck, micropenis, and cryptorchidism . The elder sister, a two and 7/12‐year‐old, had round face, hypertelorism, broad nasal bridge, narrow and high palate, redundant skin around the neck, short fingers, and hypoplastic genitalia. Their mother had microcephaly, hypertelorism, prominent colu‐ mella, broad nasal bridge, wide mouth, high palate, malaligned teeth, and clinodactyly of the fifth fingers. Serial photographs of the mother showed that the characteristic round face in infancy changed to long face with age. The present report suggests that the mother with del(18p) may be fertile, and proper genetic counseling and long follow‐up is necessary for the patient with del(18p) syndrome. © Wiley‐Liss. Inc.