Mutation spectrum of 260 dystrophinopathy patients from Turkey and important highlights for genetic counseling.

We genetically evaluated 260 dystrophinopathy patients from Turkey. Karyotyping as an initial test in female patients, followed stepwise by multiplex ligation-dependent probe amplification and by targeted next-generation sequencing of DMD revealed definitive genetic diagnoses in 214 patients (82%), with gross deletions/duplications in 153 (59%), pathogenic sequence variants in 60 (23%), and X-autosome translocation in one. Seven of the gross and 27 of the sequence variants found novel. In silico prediction, co-segregation and transcript assays supported the pathogenic nature of the novel silent (p.Lys534=) and the splice site (c.4345-12C>G) alterations. From a total of 189 singleton cases, 154 (82%) had pathogenic alterations. From 138 of those who had maternal carrier testing, 68 out of 103 (66%) showed gross and 11 out of 35 (31%) showed small pathogenic variants. This suggests that the de novo occurrences in DMD appear approximately 2.1 times more frequently in meiotic unequal crossing-over than in uncorrected replication errors. Our study also disclosed three mothers as obligate gonadal mosaic carriers. Family-based investigation of dystrophinopathy patients is crucial for the ascertainment of novel or rare variants and also for counseling and follow-up care of the families.

Novel SBF2 mutations and clinical spectrum of Charcot-Marie-Tooth neuropathy type 4B2.

Biallelic SBF2 mutations cause Charcot-Marie-Tooth disease type 4B2 (CMT4B2), a sensorimotor neuropathy with autosomal recessive inheritance and association with glaucoma. Since the discovery of the gene mutation, only few additional patients have been reported. We identified seven CMT4B2 families with nine different SBF2 mutations. Revisiting genetic and clinical data from our cohort and the literature, SBF2 variants were private mutations, including exon-deletion and de novo variants. The neuropathy typically started in the first decade after normal early motor development, was predominantly motor and had a rather moderate course. Electrophysiology and nerve biopsies indicated demyelination and excess myelin outfoldings constituted a characteristic feature. While neuropathy was >90% penetrant at age 10 years, glaucoma was absent in ~40% of cases but sometimes developed with age. Consequently, SBF2 mutation analysis should not be restricted to individuals with coincident neuropathy and glaucoma, and CMT4B2 patients without glaucoma should be followed for increased intraocular pressure. The presence of exon-deletion and de novo mutations demands comprehensive mutation scanning and family studies to ensure appropriate diagnostic approaches and genetic counseling.

Evaluation of erectile dysfunction in permanent pacemaker implanted patients with cardiac rhythm disorder prediagnosis.

BACKGROUND AND AIMS: To evaluate the anxiety, depression and related psychogenic erectile dysfunction that might be developed before and after pacemaker implantation in patients with cardiac arrhythmias. MATERIAL AND METHODS: Thirty permanent pacemaker implanted male patients, were enrolled to study between September 2006 and September 2008. Erectile function domain questions of International Index of Erectile Function (IIEF-6) and Hospital Anxiety and Depression Scale (HAD) questionnaires were applied to patients, 6 months before pacemaker implantation (BP6) and on month 1 (AP1) and 6 after application (AP6). Patients were included in a multidisciplinary cardiac rehabilitation-adaptation program with a duration of 1-2 months. Patients were evaluated in subgroups. RESULTS: Mean age was 51.5 ± 10.3. Most frequent diagnosis was observed as AV block in etiology. The mean IIEF values were changed 22.8→20.2→24.6 in BP6, AP1 and AP6 time frames consecutively. However, the mean HAD-Anxiety scores were evaluated as 8.1→17.0→7.3 and the mean HAD-Depression as 3.9→7.9→8.9 consecutively in the same time frames. CONCLUSION: Cardiac arrhythmia plus permanent pacemaker implantation, increased anxiety and depression of patients and decreased erectile function at AP1; however, the improvement in cardiac symptoms at AP6 with the possible positive effects of rehabilitation program, helps to reduce anxiety and increased IIEF scores, although there was still a slight increase in depression levels.

Lymphangioma of pyeloureteral junction: an extremely rare case.

Benign tumors of the proximal ureter are very rare. Many of them could be confused with urothelial carcinoma and unnecessarily treated by nephrectomy. In this case, we present the treatment of a lymphangioma localized in the upper ureter, which is an example of benign tumor. During treatment percutaneous tumor resection, an organ-sparing approach, was employed.

Further clinical and genetic characterization of SPG11: hereditary spastic paraplegia with thin corpus callosum.

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders leading to progressive spasticity of the lower limbs. Clinically, HSPs are divided into "pure" and "complicated" forms. In pure HSP, the spasticity of the lower limbs is the sole symptom, whereas in complicated forms additional neurological and non-neurological features are observed. Genetically, HSPs are divided into autosomal dominant (AD), autosomal recessive (AR) and X-linked (XL) forms. Up to date, 30 different HSPs are linked to different chromosomal loci and 11 genes could be defined for AR-HSP, AD-HSP and XL-HSP. SPG11, an AR-HSP (synonym: HSP11), is a complicated HSP associated with a slowly progressive spastic paraparesis, mental impairment and the development of a thin corpus callosum (TCC) during the course of the disease. SPG11 has been previously linked to chromosomal region 15q13 - 15. First, we applied rigid diagnostic criteria to systematically examine 20 Turkish families with autosomal recessive HSP for characteristic features of SPG11. We detected four large Turkish families with AR-HSP and TCC consistent with SPG11. Subsequent genetic linkage analysis of those 4 families refines the SPG11 locus further down to a small region of 2.93 cM with a maximum lod score of 11.84 at marker D15S659 and will guide further candidate gene analysis.

Novel truncating and missense mutations of the KCC3 gene associated with Andermann syndrome.

BACKGROUND: Andermann syndrome (OMIM 218000) is an autosomal recessive motor-sensory neuropathy associated with developmental and neurodegenerative defects. The cerebral MRI reveals a variable degree of agenesis of the corpus callosum. Recently, truncating mutations of the KCC3 gene (also known as SLC12A6) have been associated with Andermann syndrome. METHODS: The authors assessed clinically and genetically three isolated cases from Germany and Turkey with symptoms consistent with Andermann syndrome. RESULTS: The authors detected four novel mutations within the KCC3 gene in their patients: two different truncating mutations in the first patient, a homozygous truncating mutation in the second, and a homozygous missense mutation in the third patient. In contrast to the classic phenotype of the Andermann syndrome linked to truncating KCC3 mutations the phenotype and the course of the disease linked to the missense mutation appeared to be different (i.e., showing additional features like diffuse and widespread white matter abnormalities). CONCLUSIONS: Not only truncating but also missense mutations of the KCC3 gene are associated with Andermann syndrome. Different types of KCC3 mutations may determine different clinical phenotypes.

Extensive scanning of the calpain-3 gene broadens the spectrum of LGMD2A phenotypes.

BACKGROUND: The limb girdle muscular dystrophies (LGMD) are a heterogeneous group of Mendelian disorders highlighted by weakness of the pelvic and shoulder girdle muscles. Seventeen autosomal loci have been so far identified and genetic tests are mandatory to distinguish among the forms. Mutations at the calpain 3 locus (CAPN3) cause LGMD type 2A. OBJECTIVE: To obtain unbiased information on the consequences of CAPN3 mutations. PATIENTS: 530 subjects with different grades of symptoms and 300 controls. METHODS: High throughput denaturing HPLC analysis of DNA pools. RESULTS: 141 LGMD2A cases were identified, carrying 82 different CAPN3 mutations (45 novel), along with 18 novel polymorphisms/variants. Females had a more favourable course than males. In 94% of the more severely affected patient group, the defect was also discovered in the second allele. This proves the sensitivity of the approach. CAPN3 mutations were found in 35.1% of classical LGMD phenotypes. Mutations were also found in 18.4% of atypical patients and in 12.6% of subjects with high serum creatine kinase levels. CONCLUSIONS: A non-invasive and cost-effective strategy, based on the high throughput denaturing HPLC analysis of DNA pools, was used to obtain unbiased information on the consequences of CAPN3 mutations in the largest genetic study ever undertaken. This broadens the spectrum of LGMD2A phenotypes and sets the carrier frequency at 1:103.

Two patients with 'Dropped head syndrome' due to mutations in LMNA or SEPN1 genes.

Dropped head syndrome is characterized by severe weakness of neck extensor muscles with sparing of the flexors. It is a prominent sign in several neuromuscular conditions, but it may also be an isolated feature with uncertain aetiology. We report two children in whom prominent weakness of neck extensor muscles is associated with mutations in lamin A/C (LMNA) and selenoprotein N1 (SEPN1) genes, respectively. This report expands the underlying causes of the dropped head syndrome which may be the presenting feature of a congenital muscular dystrophy.

Localisation of merosin-positive congenital muscular dystrophy to chromosome 4p16.3.

The congenital muscular dystrophies (CMD) are a heterogeneous group of autosomal recessive disorders, which present within the first 6 months of life with hypotonia, muscle weakness and contractures, associated with dystrophic changes on skeletal muscle biopsy. We have previously reported a large consanguineous family segregating merosin-positive congenital muscular dystrophy, in which involvement of known CMD loci was excluded. A genome-wide linkage search of the family conducted using microsatellite markers spaced at 10-Mb intervals failed to identify a disease locus. A second scan using a high-density SNP array, however, permitted a novel CMD locus on 4p16.3 to be identified (multipoint LOD score 3.4). Four additional consanguineous CMD families with a similar phenotype were evaluated for linkage to a 4.14-Mb interval on 4p16.3; however, none showed any evidence of linkage to the region. Our findings further illustrate the utility of highly informative SNP arrays compared with standard panels of microsatellite markers for the mapping of recessive disease loci.

Giant axonal neuropathy: clinical and genetic study in six cases.

BACKGROUND: Giant axonal neuropathy (GAN) is a severe recessive disorder characterised by variable combination of progressive sensory motor neuropathy, central nervous system (CNS) involvement, and "frizzly" hair. The disease is caused by GAN gene mutations on chromosome 16q24.1. AIMS: To search for GAN gene mutations in Turkish patients with GAN and characterise the phenotype associated with them. METHODS: Linkage and mutation analyses were performed in six affected patients from three consanguineous families. These patients were also investigated by cranial magnetic resonance imaging (MRI) and electroencephalography (EEG). Electromyography (EMG) was performed in heterozygous carriers from family 1 and family 3. RESULTS: Linkage to 16q24.1 was confirmed by haplotype analysis. GAN mutations were identified in all families. Family 1 had the R293X mutation, previously reported in another Turkish family. Families 2 and 3, originating from close geographical areas, shared a novel mutation, 1502+1G>T, at the donor splice site of exon 9. All patients displayed a common phenotype, including peripheral neuropathy, cerebellar ataxia, and frizzly hair. Cranial MRI showed diffuse white matter abnormalities in two patients from family 1 and the patient from family 3, and minimal white matter involvement in the patient from family 2. EMG of a heterozygous R293X mutation carrier showed signs of mild axonal neuropathy, whereas a 1502+1G>T mutation carrier had normal EMG. EEG abnormalities were found in three patients. CONCLUSION: These findings highlight the association of CNS involvement, in particular white matter abnormalities, with peripheral neuropathy in GAN. The phenotypical consequences of both mutations (when homozygous) were similar.

Prednisolone therapy in Duchenne muscular dystrophy prolongs ambulation and prevents scoliosis.

Steroids may have a beneficial effect on the course of Duchenne muscular dystrophy (DMD). However, results vary in different studies. This study consisted of 66 DMD boys who were in the therapy group and 22 DMD boys in the control group. The mean ages were 6.8 +/- 2.1 years (range 2.5-12.5) and 7.0 +/- 1.3 years (range 5.0-9.0), respectively. We assessed muscle strength, 10-m walking, ankle contracture, and loss of independent walking ability age and onset of scoliosis. Treatment regimen was oral prednisolone 0.75 mg/kg on alternate days, plus vitamin D 600-1200 units/day and a calcium-enriched diet. After a follow-up period of 2.75 +/- 1.1 years (range 1.5-5) and when compared with controls, there was a statistically significant change in muscle strength between the two groups after 12 months (P < 0.05). Although 10-m walking time decreased in therapy group (P < 0.05), there was not significance between the groups in the end. Boys in the control group developed significantly less ankle contractures (P < 0.05). None of the therapy group had scoliosis during the follow-up period (mean age 10.8 +/- 1.2 years), whereas seven boys of the control group had scoliosis at a mean age of 11.7 +/- 2 years. Loss of walking ability age was statistically different between groups (P < 0.05). Our results indicate that, alternate-day prednisolone regimen may prolong ambulation and scoliosis can be delayed or prevented.

Collagen VI status and clinical severity in Ullrich congenital muscular dystrophy: phenotype analysis of 11 families linked to the COL6 loci.

Ullrich's congenital muscular dystrophy (UCMD) is an autosomal recessive myopathy characterised by neonatal muscle weakness, proximal joint contractures and distal hyperlaxity. Mutations in the COL6A1, COL6A2 (21 q22.3) and COL6A3 (2 q37) genes, encoding the alpha 1, alpha 2 and alpha 3 chains of collagen VI, respectively, have been recently identified as responsible for UCMD in a total of 9 families. We investigated in detail the clinical and morphological phenotype of 15 UCMD patients from 11 consanguineous families showing potential linkage either to 21 q22.3 (6 families) or to 2 q37 (5 families). Collagen VI deficiency was confirmed on muscle biopsies or skin fibroblasts in 8 families. Although all patients shared a common phenotype, a great variability in severity was observed. Collagen VI deficiency in muscle or cultured fibroblasts was complete in the severe cases and partial in the milder ones, which suggests a correlation between the degree of collagen VI deficiency and the clinical severity in UCMD. No significant phenotypical differences were found between the families linked to each of the 2 loci, which confirms UCMD as a unique entity with underlying genetic heterogeneity.

Clinical spectrum of muscle-eye-brain disease: from the typical presentation to severe autistic features.

Muscle-eye-brain disease (MEB) is an autosomal recessive congenital muscular dystrophy with ocular abnormalities and type II lissencephaly. MEB is caused by mutations in the protein O-linked mannose beta1,2-N-acetylglucosaminyltransferase (POMGnT1) gene on chromosome 1q33. POMGnT1 is a glycosylation enzyme that participates in the synthesis of O-mannosyl glycan. The disease is characterized by altered glycosylation of alpha-dystroglycan. The clinical spectrum of MEB phenotype and POMGnT1 mutations are significantly expanded. We would like to present two cases with MEB disease with POMGnT1 mutations, whose clinical picture shows heterogeneity. The patient with R442H mutation had the classical form of the disease although the one with IVS17-2A-->G homozygous mutation had severe autistic features as the dominating presenting sign. These two cases represent different spectrums of one disorder. To the best of our knowledge, autistic features and stereotypical movements have not been included thus far as a part of broad and heterogeneous MEB spectrum.

Beta-sarcoglycan gene mutations in Turkey.

The term limb-girdle muscular dystrophy (LGMD) refers to a group of muscular dystrophies that, at the outset, affect primarily the muscles of the hip and shoulder girdle. Limb-girdle muscular dystrophy is genetically heterogeneous comprising autosomal dominant (types LGMD 1A-1E) as well as autosomal recessive forms (types LGMD 2A-2J known). A subgroup among the autosomal recessive forms comprises the sarcoglycanopathies (LGMD2C-2F), caused by mutations in the gamma (gamma-SG), alpha (alpha-SG), beta (beta-SG) and delta (delta-SG) sarcoglycan genes, respectively. The sarcoglycans form the sarcoglycan complex, part of the dystrophin-associated glycoproteins. Mutations in the beta-SG gene causes LGMD2E. Disease severity, in this form, varies from mild to severe phenotypes depending on the individual mutation. Homozygous missense mutations in critical locations may result in the total absence of alpha-, beta- and gamma-sarcoglycan from the muscle membrane and a phenotype as severe as null mutations. In the present study, through screening 80 unrelated LGMD2 families, we identified 13 families with LGMD2E. Mutations in the beta-SG gene were identified in 12 patients from nine families. One of these patients carried a previously reported truncating mutation (Q11X), while the other 11 carried novel missense/rameshift mutations (M1L, V89M, I92T, I92S, 739insA), some of which were seen in more than one patient and may, therefore, be more common in the Turkish population.

FKRP gene mutations cause congenital muscular dystrophy, mental retardation, and cerebellar cysts.

BACKGROUND: Congenital muscular dystrophies (CMD) are autosomal recessive disorders that present within the first 6 months of life with hypotonia and a dystrophic muscle biopsy. CNS involvement is present in some forms. The fukutin-related protein gene (FKRP) is mutated in a severe form of CMD (MDC1C) and a milder limb girdle dystrophy (LGMD2I). Both forms have secondary deficiencies of laminin alpha2 and alpha-dystroglycan immunostaining. Structural brain involvement has not been observed in patients with FKRP gene mutations. METHODS: The authors studied two unrelated patients who had a pattern of muscle involvement identical to MDC1C, mental retardation, and cerebellar cysts on cranial MRI. The FKRP gene was analyzed along with the skeletal muscle expression of laminin alpha2 and alpha-dystroglycan. RESULTS: The muscle biopsy of both patients showed severe dystrophic findings, a reduction in laminin alpha2, and profound depletion of alpha-dystroglycan. Both patients had homozygous FKRP gene mutations not previously reported (C663A [Ser221Arg] and C981A [Pro315Thr]). CONCLUSIONS: Mutations within the FKRP gene can result in CMD associated with mental retardation and cerebellar cysts. This adds structural brain defects to the already wide spectrum of abnormalities caused by FKRP mutations. The severe depletion of alpha-dystroglycan expression suggests that FKRP is involved in the processing of alpha-dystroglycan.

Mutations in GDAP1: autosomal recessive CMT with demyelination and axonopathy.

BACKGROUND: Mutations in the ganglioside-induced differentiation-associated protein 1 gene (GDAP1) were recently shown to be responsible for autosomal recessive (AR) demyelinating Charcot-Marie-Tooth disease (CMT) type 4A (CMT4A) as well as AR axonal CMT with vocal cord paralysis. METHODS: The coding region of GDAP1 was screened for the presence of mutations in seven families with AR CMT in which the patients were homozygous for markers of the CMT4A locus at chromosome 8q21.1. RESULTS: A nonsense mutation was detected in exon 5 (c.581C>G, S194X), a 1-bp deletion in exon 6 (c.786delG, G262fsX284), and a missense mutation in exon 6 (c.844C>T, R282C). CONCLUSIONS: Mutations in GDAP1 are a frequent cause of AR CMT. They result in an early-onset, severe clinical phenotype. The range of nerve conduction velocities (NCV) is variable. Some patients have normal or near normal NCV, suggesting an axonal neuropathy, whereas others have severely slowed NCV compatible with demyelination. The peripheral nerve biopsy findings are equally variable and show features of demyelination and axonal degeneration.