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Biomedical subjects

E Bertini

Publications and source records attributed to E Bertini.

At least 37 records · Page 2Linked to original sources

The effect of genotype on the natural history of eIF2B-related leukodystrophies.

BACKGROUND: Recessive mutations in the five eucaryotic initiation factor 2B (eIF2B) subunits have been found in leukodystrophies of variable age at onset and severity. OBJECTIVES: To evaluate the clinical spectrum of eIF2B-related disorders and search for a phenotype-genotype correlation. METHODS: Ninety-three individuals (78 families) with an undetermined leukodystrophy were selected on MRI-based criteria of childhood ataxia with central hypomyelination/vanishing white matter (CACH/VWM) for EIF2B genes analysis. RESULTS: Eighty-nine percent of individuals with MRI criteria of CACH/VWM have a mutation in one of the eIF2B beta to epsilon subunits. For 83 individuals (68 families), 46 distinct mutations (90% missense) in four of the five eIF2B subunits (beta, gamma, delta, epsilon) were identified. Sixty-four percent were in the epsilon subunit, a R113H substitution was found in 71% of eIF2B epsilon-mutated families. A large clinical spectrum was observed from rapidly fatal infantile to asymptomatic adult forms. Disease severity was correlated with age at onset (p < 0.0001) but not with the type of the mutated subunit nor with the position of the mutation within the protein. Mutations R113H in the epsilon subunit and E213G in the beta subunit were significantly associated with milder forms. CONCLUSIONS: The degree of eIF2B dysfunction, which is involved in the regulation of protein synthesis during cellular stress, may play a role in the clinical expression of eIF2B-related disorders.

Adolescent↗

Clinical and genetic studies in hereditary spastic paraplegia with thin corpus callosum.

BACKGROUND: A complicated form of recessive hereditary spastic paraplegias (HSPs) with thin corpus callosum (TCC) was first described in Japan, and most of the Japanese families showed linkage to chromosome 15q13-15. A recessive HSP locus (SPG11) has also been mapped to chromosome 15q13-15 in Italian and North American families with and without TCC, and it overlaps the region identified in the Japanese families. OBJECTIVE: To study clinically and genetically 12 Italian families with HSP and TCC. METHODS: The authors investigated 18 affected and 30 healthy individuals from 12 unrelated Italian families with recessive HSP-TCC. Clinical, neurophysiologic, and neuroradiologic studies were undertaken. All patients were negative for SPG7 mutations. Genetic linkage analyses were carried out with polymorphic DNA markers on 15q13-15. RESULTS: Five families were consistent with linkage, thus defining a 19.8-cM region between markers D15S1007 and D15S978, encompassing the SPG11 interval. In one consanguineous family, linkage could be firmly excluded, confirming genetic heterogeneity. Two families appeared not linked to the region, but this could not be firmly proved because of the small family size. The remaining four families were uninformative for linkage purposes. CONCLUSION: HSP-TCC is common in Italy. The phenotype is fairly homogeneous and is associated with impaired cognition. There are at least two loci for HSP-TCC, one of which is on chromosome 15q13-15.

Adolescent↗

Clinical and molecular findings in patients with giant axonal neuropathy (GAN).

Giant axonal neuropathy (GAN) is a rare autosomal recessive neurodegenerative disorder of early onset, clinically characterized by a progressive involvement of both peripheral and CNS. The diagnosis is based on the presence of characteristic giant axons, filled with neurofilaments, on nerve biopsy. Recently, the defective protein, gigaxonin, has been identified and different pathogenic mutations in the gigaxonin gene have been reported as the underlying genetic defect. Gigaxonin, a member of the BTB/kelch superfamily proteins, seems to play a crucial role in the cross talk between the intermediate filaments and the membrane network. The authors report clinical and molecular findings in five Italian patients with GAN. This study shows the allelic heterogeneity of GAN and expands the spectrum of mutations in the GAN gene. The frequent occurrence of private mutations stresses the importance of a complete gene analysis.

Adolescent↗

Novel SACS mutations in autosomal recessive spastic ataxia of Charlevoix-Saguenay type.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset familial disease with prominent myelinated fibers in the optic fundus. ARSACS is frequent in the Charlevoix-Saguenay region of Quebec but rare elsewhere. Mutations in SACS, encoding sacsin, a protein of unknown function, are associated with ARSACS. The authors identified three new SACS mutations in two Italian patients whose phenotype closely matches that of Quebec cases, but without retinal striation.

Adult↗

Severe abnormalities of the pons in two infants with goldenhar syndrome.

We describe 2 cases of Goldenhar syndrome with severe abnormalities of the pons. The first case is a 10-month-old Caucasian female infant. At birth the girl showed polydactyly, labiopalatoschisis, right ear agenesis, left eye coloboma and vertebral anomalies. She also had marked hypotonia, severely reduced movements and respiratory and feeding abnormalities. She required gastrostomy at 5 months and tracheostomy at 7 months. Brain MRI scans showed moderate cerebellar hypoplasia and severe abnormalities of the pons with a congenital cleft. The child died at age 12 months. Case 2 is a Caucasian boy. Clinical signs and presentation were similar to case 1. The child also had severely reduced lacrimation, sweating, with thermoregulation abnormalities. He also underwent gastrostomy at 18 months. The child is now 3 years old and is able to sit only with support. Brain MRI was similar to case 1. The association of Goldenhar syndrome and pons abnormalities in 2 subjects suggests that this is more than a mere coincidence. Further studies and characterization of the genes involved in Goldenhar syndrome are needed to establish an adequate genotype-phenotype correlation.

Abnormalities, Multiple↗

A mitochondrial ATPase 6 mutation is associated with Leigh syndrome in a family and affects proton flow and adenosine triphosphate output when modeled in Escherichia coli.

A multidisciplinary strategy was used to identify the molecular defect in a family with Leigh syndrome (LS). The propositus presented severe developmental delay, an ataxic-spastic gait and seizures. She died at 3.5 y of age from cardiorespiratory arrest. Postmortem examination disclosed pathological features typical of LS. A 12-y-old sister is affected with the same disease. Respiratory chain enzyme complex activities in skeletal muscle biopsy were normal. Adenosine triphosphate (ATP) synthesis during oxidative phosphorylation in skin fibroblasts mitochondria showed a severely hampered ATP production. Mitochondrial DNA sequencing revealed a new mutation in the ATPase 6 gene (T9176G). Site-directed mutagenesis in Escherichia coli strains was used to measure H+ pumping and ATP synthesis. Results were comparable to findings obtained in human cells. These data corroborate the use of E. coli strains as a feasible "animal" model for functional studies in pathogenic mutations of the ATPase 6 gene.

Child↗

Genetic heterogeneity of megalencephalic leukoencephalopathy and subcortical cysts.

Reported are the clinical, neuroradiologic, and molecular findings in 18 patients with megalencephalic leukoencephalopathy and subcortical cysts (MLC) syndrome. Marked clinical intrafamilial and interfamilial variability in mutation-proven cases was found. A broad spectrum of pathogenetic mutations (missense, splice site, insertion, and deletions) were identified in the MLC1 gene, enlarging the spectrum of allelic variants without a straightforward genotype-phenotype correlation. Five patients did not harbor mutations in MLC1, supporting the existence of at least one other MLC locus.

Adolescent↗

Spectrum of SCN1A mutations in severe myoclonic epilepsy of infancy.

OBJECTIVES: SCN1A mutations were recently reported in several patients with severe myoclonic epilepsy in infancy (SMEI). The authors analyzed SCN1A mutations in 93 patients with SMEI and made genotype-phenotype correlation to clarify the role of this gene in the etiology of SMEI. METHODS: All patients fulfilled the criteria for SMEI. The authors analyzed all patients for SCN1A mutations using denaturing high performance liquid chromatography. If a patient's chromatogram was abnormal, the authors sequenced the gene in the patient and both parents. RESULTS: SCN1A mutations were identified in 33 patients (35%). Most mutations were de novo, but were inherited in three patients. Parents carrying the inherited mutations had either no symptoms or a milder form of epilepsy. A greater frequency of unilateral motor seizures was the only clinical difference between patients with SCN1A mutations and those without. Truncating mutations were more frequently associated with such seizures than were missense mutations. The percentage of cases with family history of epilepsy was significantly higher in patients with SCN1A mutations. CONCLUSIONS: Unilateral motor seizures may be a specific clinical characteristic of SMEI caused by SCN1A mutations. Ten percent of SCN1A mutations are inherited from an asymptomatic or mildly affected parent, suggesting that SMEI is genetically heterogeneous. The increased frequency of familial epilepsy indicates that other genetic factors may contribute to this disorder.

Adult↗

Cerebellar ataxia and coenzyme Q10 deficiency.

The authors measured coenzyme Q10 (CoQ10) concentration in muscle biopsies from 135 patients with genetically undefined cerebellar ataxia. Thirteen patients with childhood-onset ataxia and cerebellar atrophy had markedly decreased levels of CoQ10. Associated symptoms included seizures, developmental delay, mental retardation, and pyramidal signs. These findings confirm the existence of an ataxic presentation of CoQ10 deficiency, which may be responsive to CoQ10 supplementation.

Adolescent↗

Infantile ascending hereditary spastic paralysis (IAHSP): clinical features in 11 families.

OBJECTIVE: To report clinical, neuroradiologic, neurophysiologic, and genetic findings on 16 patients from 11 unrelated families with a remarkable uniform phenotype characterized by infantile ascending hereditary spastic paralysis (IAHSP). METHODS: Sixteen patients from 11 families, originating from North Africa and Europe, who presented severe spastic paralysis and ascending progression were studied. RESULTS: Spastic paraplegia started in the first 2 years of life in most patients and extended to the upper limbs by the end of the first decade. The disease progressed to tetraplegia, anarthria, dysphagia, and slow eye movements in the second decade. The clinical course showed a long survival and preservation of intellectual skills. Clinical, neuroradiologic, and neurophysiologic findings were consistent with a relatively selective early involvement of the corticospinal and corticobulbar pathways. No signs of lower motor neuron involvement were observed, whereas motor evoked potentials demonstrated predominant involvement of the upper motor neurons. MRI was normal in young patients but showed brain cortical atrophy in the oldest, predominant in the motor areas, and T2-weighted bilateral hyperintense signals in the posterior arm of the internal capsule. The ALS2 gene, recently found mutated in consanguineous Arabic families with either an ALS2 phenotype or a juvenile-onset primary lateral sclerosis, was analyzed. Alsin mutations were found in only 4 of the 10 families, whereas haplotype analysis excluded the ALS2 locus in one family. CONCLUSIONS: The syndrome of IAHSP is genetically heterogeneous, and no clinical sign can help to distinguish patients with and without Alsin mutations.

Adolescent↗

Mutation analysis in 16 patients with mtDNA depletion.

Sixteen unrelated Southern European patients with the mitochondrial depletion syndrome (MDS) were analyzed for mutations in the TK2 and DGUOK genes. Three novel mutations were identified in TK2 (R183G, R254X, and 142insG). When we analyzed additional genes involved in the dNTPs pool, such as SLC25A19 (DNC) and NT5M (d-NT2), we did not detect mutations. The current study suggest that scanning the TK2, DGUOK, SLC25A19, and NT5M genes is likely to help about 10% of MDS families in terms of genetic counseling. Also, our findings indicate that genotype-phenotype correlations are not straightforward in MDS.

Age of Onset↗

SPG3A: An additional family carrying a new atlastin mutation.

The authors report on a novel frameshift mutation (c.1688insA) in the SPG3A gene resulting in premature translation termination of the gene product atlastin. These data add a new variant to the second disease gene in autosomal dominant hereditary spastic paraplegia (ADHSP) and lend definitive support to its causative role. By combining direct testing of SPAST and SPG3A, at least 50% of ADHSP families can now receive appropriate genetic diagnosis.

Adult↗

A severe variant of childhood ataxia with central hypomyelination/vanishing white matter leukoencephalopathy related to EIF21B5 mutation.

Childhood ataxia with central hypomyelination (CACH)/vanishing white matter (VWM) leukoencephalopathy is related to mutations in all five genes of the eukaryotic translation initiation factor (eIF2B). In a fatal infantile leukoencephalopathy, which the authors previously classified as a severe variant of CACH/VWM, a new homozygous missense mutation in the EIF2B5 gene was found. Abnormal decrease in blood uric acid and increase of erythrocyte guanosine 5'-diphosphate sugars found in two siblings may contribute to the explanation of this particularly severe condition.

Ataxia↗