Clinical application of next generation sequencing in hereditary spinocerebellar ataxia: increasing the diagnostic yield and broadening the ataxia-spasticity spectrum. A retrospective analysis.

One of the hardest challenges in medical genetics is to reach a molecular diagnosis in the presence of rare brain disorders. Hereditary spinocerebellar ataxia (HA), characterized by high clinical and genetic heterogeneity, is among the diseases that present this challenge. HA can have features overlapping with those of other neurological diseases, especially hereditary spastic paraplegia (HSP), as routine clinical application of next generation sequencing (NGS) has confirmed.

Congenital myopathies: clinical phenotypes and new diagnostic tools.

Congenital myopathies are a group of genetic muscle disorders characterized clinically by hypotonia and weakness, usually from birth, and a static or slowly progressive clinical course. Historically, congenital myopathies have been classified on the basis of major morphological features seen on muscle biopsy. However, different genes have now been identified as associated with the various phenotypic and histological expressions of these disorders, and in recent years, because of their unexpectedly wide genetic and clinical heterogeneity, next-generation sequencing has increasingly been used for their diagnosis.

CYP2U1 activity is altered by missense mutations in hereditary spastic paraplegia 56.

Hereditary spastic paraplegia (HSP) is an inherited disorder of the central nervous system mainly characterized by gradual spasticity and weakness of the lower limbs. SPG56 is a rare autosomal recessive early onset complicated form of HSP caused by mutations in CYP2U1. The CYP2U1 enzyme was shown to catalyze the hydroxylation of arachidonic acid.

The Networks of Genes Encoding Palmitoylated Proteins in Axonal and Synaptic Compartments Are Affected in PPT1 Overexpressing Neuronal-Like Cells.

CLN1 disease (OMIM #256730) is an early childhood ceroid-lipofuscinosis associated with mutated , whose product Palmitoyl-Protein Thioesterase 1 (PPT1) is a lysosomal enzyme involved in the removal of palmitate residues from S-acylated proteins. In neurons, PPT1 expression is also linked to synaptic compartments. The aim of this study was to unravel molecular signatures connected to .

Revisiting mitochondrial ocular myopathies: a study from the Italian Network.

Ocular myopathy, typically manifesting as progressive external ophthalmoplegia (PEO), is among the most common mitochondrial phenotypes. The purpose of this study is to better define the clinical phenotypes associated with ocular myopathy. This is a retrospective study on a large cohort from the database of the "Nation-wide Italian Collaborative Network of Mitochondrial Diseases".

Autosomal recessive spastic ataxia of Charlevoix-Saguenay: a family report from South Brazil.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset, neurodegenerative disorder caused by mutations in SACS, firstly reported in Quebec, Canada. The disorder is typically characterized by childhood onset ataxia, spasticity, neuropathy and retinal hypermyelination. The clinical picture of patients born outside Quebec, however, is often atypical.

Possible Involvement of the CACNA1E Gene in Migraine: A Search for Single Nucleotide Polymorphism in Different Clinical Phenotypes.

Objective: To search for differences in prevalence of a CACNA1E variant between migraine without aura, various phenotypes of migraine with aura, and healthy controls.

Background: Familial hemiplegic migraine type 1 (FHM1) is associated with mutations in the CACNA1A gene coding for the alpha 1A (Ca 2.1) pore-forming subunit of P/Q voltage-dependent Ca channels.

Phenotype and natural history of variant late infantile ceroid-lipofuscinosis 5.

Aim: To characterize the phenotypic profile of a cohort of children affected with CLN5, a rare form of neuronal ceroid-lipofuscinosis (NCL), and to trace the features of the natural history of the disease.

Method: Records of 15 children (nine males, six females) were obtained from the data sets of the DEM-CHILD International NCL Registry. Disease progression was measured by rating six functional domains at different time points along the disease course.

Neutral Lipid Storage Diseases: clinical/genetic features and natural history in a large cohort of Italian patients.

Background: A small number of patients affected by Neutral Lipid Storage Diseases (NLSDs: NLSD type M with Myopathy and NLSD type I with Ichthyosis) have been described in various ethnic groups worldwide. However, relatively little is known about the progression and phenotypic variability of the disease in large specific populations. The aim of our study was to assess the natural history, disability and genotype-phenotype correlations in Italian patients with NLSDs.

Novel mutations in provide clues to the pathomechanisms of HSAN-VI.

Objective: To describe a second hereditary sensory autonomic neuropathy type VI (HSAN-VI) family harboring 2 novel heterozygous mutations in the dystonin () gene and to evaluate their effect on neurons derived from induced pluripotent stem cells (iPSC).

Methods: The family consisted of 3 affected siblings from nonconsanguineous healthy parents. All members underwent clinical and electrophysiologic evaluation and genetic analysis.

Mutations in GMPPB Presenting with Pseudometabolic Myopathy.

Mutations in the guanosine diphosphate mannose (GDP-mannose) pyrophosphorylase B (GMPPB) gene encoding a key enzyme of the glycosylation pathway have been described in families with congenital (CMD) and limb girdle (LGMD) muscular dystrophy with reduced alpha-dystroglycan (α-DG) at muscle biopsy.Patients typically display a combined phenotype of muscular dystrophy, brain malformations, and generalized epilepsy. However, a wide spectrum of clinical severity has been described ranging from classical CMD presentation to children with mild, yet progressive LGMD with or without intellectual disability.

Leigh-like neuroimaging features associated with new biallelic mutations in OPA1.

Behr syndrome is characterized by the association of early onset optic atrophy, cerebellar ataxia, pyramidal signs, peripheral neuropathy and mental retardation. Recently, some cases were reported to be caused by biallelic mutations in OPA1. We describe an 11-year-old girl (Pt1) and a 7-year-old boy (Pt2) with cognitive delay, ataxic gait and clinical signs suggestive of a peripheral neuropathy, with onset in early infancy.

Learning disabilities in neuromuscular disorders: a springboard for adult life.

Although the presence of cognitive deficits in Duchenne muscular dystrophy or myotonic dystrophy DM1 is well established in view of brain-specific expression of affected muscle proteins, in other neuromuscular disorders, such as congenital myopathies and limb-girdle muscular dystrophies, cognitive profiles are poorly defined. Also, there are limited characterization of the cognitive profile of children with congenital muscular dystrophies, notwithstanding the presence of cerebral abnormality in some forms, and in spinal muscular atrophies, with the exception of distal spinal muscular atrophy (such as the DYN1CH1- associated form). Starting from the Duchenne muscular dystrophy, which may be considered a kind of paradigm for the co-occurrence of learning disabilities in the contest of a progressive muscular involvement, the findings of neuropsychological (or cognitive) dysfunctions in several forms of neuromuscular diseases will be examined and reviewed.

SPG2 mimicking multiple sclerosis in a family identified using next generation sequencing.

Several single gene disorders can potentially be overlooked in the differential diagnostic evaluation of patients with multiple sclerosis (MS). Pelizaeus-Merzbacher disease and spastic paraplegia type 2 are allelic X-linked disorders associated with defective myelination of the central nervous system and mutations in PLP1. Neurological symptoms are occasionally observed in female carriers of these mutations.

Widening the Heterogeneity of Leigh Syndrome: Clinical, Biochemical, and Neuroradiologic Features in a Patient Harboring a NDUFA10 Mutation.

Leigh syndrome (LS) is an early-onset progressive neurodegenerative disorder, characterized by a wide clinical and genetic heterogeneity, and is the most frequent disorder of mitochondrial energy production in children. Beside its great variability in clinical, biochemical, and genetic features, LS is pathologically uniformly characterized by multifocal bilateral and symmetric spongiform degeneration of the basal ganglia, brainstem, thalamus, cerebellum, spinal cord, and optic nerves. Isolated complex I deficiency is the most common defect identified in Leigh syndrome.

Loss of spatacsin function alters lysosomal lipid clearance leading to upper and lower motor neuron degeneration.

Mutations in SPG11 account for the most common form of autosomal recessive hereditary spastic paraplegia (HSP), characterized by a gait disorder associated with various brain alterations. Mutations in the same gene are also responsible for rare forms of Charcot-Marie-Tooth (CMT) disease and progressive juvenile-onset amyotrophic lateral sclerosis (ALS). To elucidate the physiopathological mechanisms underlying these human pathologies, we disrupted the Spg11 gene in mice by inserting stop codons in exon 32, mimicking the most frequent mutations found in patients.

Fast Progression of Cerebellar Atrophy in PLA2G6-Associated Infantile Neuronal Axonal Dystrophy.

Infantile neuronal axonal dystrophy (INAD) is characterized by progressive cerebellar atrophy. MRI has been recommended as a marker of disease progression in cerebellar diseases. We performed a longitudinal brain volumetry study in a couple of bicorial twins with PLA2G6-positive INAD.