Protein- and mRNA-based phenotype-genotype correlations in DMD/BMD with point mutations and molecular basis for BMD with nonsense and frameshift mutations in the DMD gene.

Straightforward detectable Duchenne muscular dystrophy (DMD) gene rearrangements, such as deletions or duplications involving an entire exon or more, are involved in about 70% of dystrophinopathies. In the remaining 30% a variety of point mutations or "small" mutations are suspected. Due to their diversity and to the large size and complexity of the DMD gene, these point mutations are difficult to detect.

Disease severity in dominant Emery Dreifuss is increased by mutations in both emerin and desmin proteins.

Individuals with the same genetic disorder often show remarkable differences in clinical severity, a finding generally attributed to the genetic background. We identified two patients with genetically proven Emery-Dreifuss muscular dystrophy (EDMD) who followed an unusual course and had uncommon clinicopathological findings. We hypothesized digenic inheritance and looked for additional molecular explanations.

X-linked Emery-Dreifuss muscular dystrophy and vacuoles: an immunohistochemical characterization.

We report a striking abundance of rimmed vacuoles in two brothers with X-linked Emery-Dreifuss muscular dystrophy (X-EDMD) confirmed by the absence of emerin at the muscular nuclear envelope and by genetic analysis showing a new 2-bp deletion in exon 6 of the STA gene at the Xq28 region. Immunohistochemical analysis of the vacuoles revealed expression of dystrophin but not of merosin in the sarcolemma of rimmed vacuoles and absence of amyloid and membrane attack complex (MAC) deposition either in vacuoles or muscle fibers. The presence of rimmed vacuoles can be a histopathological finding in X-EDMD, and the diagnosis should not be excluded in clinically well-defined EDMD patients because of this finding.

Phase I study of dystrophin plasmid-based gene therapy in Duchenne/Becker muscular dystrophy.

Nine patients with Duchenne or Becker muscular dystrophy were injected via the radialis muscle with a full-length human dystrophin plasmid, either once with 200 or 600 microg of DNA or twice, 2 weeks apart, with 600 microg of DNA. In the biopsies taken 3 weeks after the initial injection, the vector was detected at the injection site in all patients. Immunohistochemistry and nested reverse transcription-polymerase chain reaction indicated dystrophin expression in six of nine patients.

The role of muscle biopsy in analysis of the dystrophin gene in Duchenne muscular dystrophy: experience of a national referral centre.

Although the majority (65%) of boys with Duchenne muscular dystrophy (DMD) carry a deletion in the dystrophin gene, finding mutations in the remaining families is vital for counselling. We have provided a comprehensive mutation service as a national referral centre for France for over 10 years and we report here our experience. Mutation screening is on mRNA from a muscle biopsy.

Dystrophinopathy caused by mid-intronic substitutions activating cryptic exons in the DMD gene.

In the course of a mutation search performed by muscle dystrophin transcript analysis in 72 Duchenne and Becker Muscular Dystrophies (DMD/BMD) patients without gross gene defect, we encountered four unrelated cases with additional out-of-frame sequences precisely intercalated between two intact exons of the mature muscle dystrophin mRNA. An in silico search of the whole dystrophin genomic sequence revealed that these inserts correspond to cryptic exons flanked by one strong and one weak consensus splice site and located in the mid-part of large introns (introns 60, 9, 1M, and 62, respectively). In each case we identified an intronic point mutation activating the cryptic donor or acceptor splice site.

Looking under every rock: Duchenne muscular dystrophy and traditional Chinese medicine.

Traditional Chinese medicine has been advocated to alleviate symptoms in Duchenne muscular dystrophy. To investigate this hypothesis, a pilot study was carried out in Beijing on 10 DMD boys treated with various regimens, including pills, decoctions, massages and acupuncture at various stages of their disease course. Despite the limited scientific impact of such a study, it seems as if the benefit, if any, is minimal.

[Symptomatic carriers of dystrophinopathy with chromosome X inactivation bias].

Several studies have recently highlighted the fact that the clinical involvement in females carrying a mutation in the dystrophin gene could be more frequent than usually thought, suggesting the need of a careful cardiac follow-up. Except for the classical chromosomal rearrangements, it was shown that a bias in the X chromosome inactivation process could be found in some affected females. We report two families illustrating different situations.

Skewed X-chromosome inactivation pattern in SRY positive XX maleness: a case report and review of literature.

XX maleness is the most common condition in which testes develop in the absence of a cytogenetically detectable Y chromosome. Using fluorescence in situ hybridization (FISH) or PCR, it was possible to detect the transfer of Yp fragments including SRY gene to the terminal part of X chromosome in the majority of XX males. We report a 32-year-old-male in whom a seminal analysis showed azoospermia, an X chromatin analysis showed 44% of Barr body positive nuclei and a chromosomal analysis revealed a 46,XX karyotype.

Pseudo-metabolic presentation in a Duchenne muscular dystrophy symptomatic carrier with 'de novo' duplication of dystrophin gene.

We report a 6-year-old female patient presenting with a sudden and severe single episode of rhabdomyolysis in which screening for a metabolic disorder was negative. Four months after the episode a muscle biopsy was performed and showed a mild pattern of necrosis/regeneration. Upon immunofluorescence, a mosaic pattern of dystrophin deficiency was found, and in the dystrophin deficient muscle fibres, the four proteins of the sarcoglycan complex were also lacking.

Clinical variability and molecular diagnosis in a four-generation family with X-linked Emery-Dreifuss muscular dystrophy.

Aim: To describe the clinical variability of X-linked Emery-Dreifuss muscular dystrophy (X-EDMD) with cardiac involvement in a four-generation family with a novel mutation in the STA gene.

Methods: Clinical data were provided for 4 affected males and a female carrier. The Western blot analysis of emerin was performed on lymphoblastoid cell lines and followed by sequencing of the emerin gene.

Clinical and molecular genetic spectrum of autosomal dominant Emery-Dreifuss muscular dystrophy due to mutations of the lamin A/C gene.

Emery-Dreifuss muscular dystrophy (EDMD) is characterized by early contractures of the elbows and Achilles tendons, slowly progressive muscle wasting and weakness, and life-threatening cardiomyopathy with conduction blocks. We recently identified LMNA encoding two nuclear envelope proteins, lamins A and C, to be implicated in the autosomal dominant form of EDMD. Here, we report on the variability of the phenotype and spectrum of LMNA mutations in 53 autosomal dominant EDMD patients (36 members of 6 families and 17 sporadic cases).

Linkage of X-linked myopathy with excessive autophagy (XMEA) to Xq28.

X-linked myopathy with excessive autophagy (XMEA, MIM 310440) is a rare inherited mild myopathy. We have used 32 polymorphic markers spanning the entire X chromosome to exclude most of the chromosome except the Xq28 region in a large XMEA family. Using three additional families for linkage analysis, we have obtained a significant two-point lod score with marker DXS1183 (Z = 2.

A novel mutation in DAX1 causes delayed-onset adrenal insufficiency and incomplete hypogonadotropic hypogonadism.

Mutations in the DAX1 gene cause X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HHG). In affected boys, primary adrenal insufficiency occurs soon after birth or during early childhood; HHG is recognized at the expected time of puberty. In this report, we describe the novel phenotype of a man who presented with apparently isolated adrenal insufficiency at 28 years of age.

Early presentation of X-linked Emery-Dreifuss muscular dystrophy resembling limb-girdle muscular dystrophy.

Emery-Dreifuss muscular dystrophy is an X-linked neuromuscular disorder caused by defects in the STA gene on Xq28, which codes for a nuclear protein named emerin. Affected patients usually present in early adolescence with scapulo-peroneal muscle weakness and wasting, and contractures of the tendo Achilles, elbows and paraspinal muscles, resulting in spine rigidity. We present here a case of Emery-Dreifuss muscular dystrophy with an unusually severe, early presentation.

Mutations in Emery-Dreifuss muscular dystrophy and their effects on emerin protein expression.

Seventeen families with Emery-Dreifuss muscular dystrophy (EDMD) have been studied both by DNA sequencing and by emerin protein expression. Fourteen had mutations in the X-linked emerin gene, while three showed evidence of autosomal inheritance. Twelve of the 14 emerin mutations caused early termination of translation.

Novel recurrent nonsense mutation causing neurofibromatosis type 1 (NF1) in a family segregating both NF1 and Noonan syndrome.

Neurofibromatosis type 1 (NF1), a genetic disorder with neuroectodermal involvement, demonstrates phenotypic overlap in some patients with Noonan syndrome (NS), ultimately resulting in the so-called neurofibromatosis-Noonan syndrome (NF-NS). A strong association of the two phenotypic traits was recently illustrated by a four-generation family, although NF1 and NS were eventually demonstrated to segregate independently on the basis of polymorphic DNA markers [Bahuau et al., 1996: Am J Med Genet 66:347-355].

A point mutation in the glycerol kinase gene associated with a deletion in the dystrophin gene in a familial X-linked muscular dystrophy: non-contiguous gene syndrome involving Becker muscular dystrophy and glycerol kinase loci.

We report a family with an X-linked recessive muscular dystrophy characterised by exercise-induced myalgia, recurrent pigmenturia and mild proximal muscle involvement. Immunocytochemical and immunoblotting analysis in muscle, using the antibody directed against the rod domain of dystrophin, revealed a loss of immunoreactivity, but the immunolabelling using the antibodies directed against the COOH and NH2 domains of dystrophin were almost normal. The immunoreactions for alpha-sarcoglycan, gamma-sarcoglycan and beta-dystroglycan were normal.

Identification by STS PCR screening of a microdeletion in Xp21.3-22.1 associated with non-specific mental retardation.

X-linked non-specific mental retardation (MRX) is a heterogeneous condition in which mental retardation (MR) appears to be the only consistent manifestation. The genetic and phenotypic heterogeneity exclude any possibility of pooling families and, therefore, of fine-mapping the related disease genes. In order to identify genomic critical regions involved in the MRX condition assigned to Xp21.

Sporadic lower limb hypertrophy and exercise induced myalgia in a woman with dystrophin gene deletion.

A 25 year old woman, without family history of muscular dystrophy, had had an isolated lower limb hypertrophy since infancy and later experienced exercise-induced myalgia. Genomic DNA analysis showed a deletion of exons 45 to 52 of the dystrophin gene. Uncommon phenotypes of dystrophinopathies and consequences in genetic counselling in women are emphasised.

Primary adhalinopathy: a common cause of autosomal recessive muscular dystrophy of variable severity.

Marked deficiency of muscle adhalin, a 50 kDa sarcolemmal dystrophin-associated glycoprotein, has been reported in severe childhood autosomal recessive muscular dystrophy (SCARMD). This is a Duchenne-like disease affecting both males and females first described in Tunisian families. Adhalin deficiency has been found in SCARMD patients from North Africa Europe, Brazil, Japan and North America (SLR & KPC, unpublished data).

Mutations in the DAX-1 gene give rise to both X-linked adrenal hypoplasia congenita and hypogonadotropic hypogonadism.

Adrenal hypoplasia congenita (AHC) is an X-linked disorder characterized by primary adrenal insufficiency. Hypogonadotropic hypogonadism (HHG) is frequently associated with this disorder but is thought not to be caused by the low adrenal androgen levels due to adrenal hypoplasia. It is uncertain whether there are two distinct yet physically linked genes responsible for AHC and HHG or a single gene responsible for both diseases.

Additional case of female monozygotic twins discordant for the clinical manifestations of Duchenne muscular dystrophy due to opposite X-chromosome inactivation.

A pair of female monozygotic (MZ) twins, heterozygous carriers for a deletion in the DMD gene and discordant for the clinical manifestations of Duchenne muscular dystrophy, were analyzed by molecular studies, in situ hybridization, and methylation pattern of X chromosomes to search for opposite X inactivation as an explanation of their clinical discordance. Results in lymphocytes and skin fibroblast cell lines suggest a partial mirror inactivation with the normal X chromosome preferentially active in the unaffected twin, and the maternal deleted X chromosome preferentially active in the affected twin. A review shows that MZ female twins discordant for X-linked diseases are not uncommon.