Expanding the phenotypic spectrum of TRAPPC11-related muscular dystrophy: 25 Roma individuals carrying a founder variant.

BACKGROUND: Limb-girdle muscular dystrophies (LGMD) are a heterogeneous group of genetically determined muscle disorders. TRAPPC11-related LGMD is an autosomal-recessive condition characterised by muscle weakness and intellectual disability. METHODS: A clinical and histopathological characterisation of 25 Roma individuals with LGMD R18 caused by the homozygous TRAPPC11 c.1287+5G>A variant is reported. Functional effects of the variant on mitochondrial function were investigated. RESULTS: The c.1287+5G>A variant leads to a phenotype characterised by early onset muscle weakness, movement disorder, intellectual disability and elevated serum creatine kinase, which is similar to other series. As novel clinical findings, we found that microcephaly is almost universal and that infections in the first years of life seem to act as triggers for a psychomotor regression and onset of seizures in several individuals with TRAPPC11 variants, who showed pseudometabolic crises triggered by infections. Our functional studies expanded the role of TRAPPC11 deficiency in mitochondrial function, as a decreased mitochondrial ATP production capacity and alterations in the mitochondrial network architecture were detected. CONCLUSION: We provide a comprehensive phenotypic characterisation of the pathogenic variant TRAPPC11 c.1287+5G>A, which is founder in the Roma population. Our observations indicate that some typical features of golgipathies, such as microcephaly and clinical decompensation associated with infections, are prevalent in individuals with LGMD R18.

Clinical and molecular diagnosis of non-phosphomannomutase 2 N-linked congenital disorders of glycosylation in Spain.

The congenital disorders of glycosylation (CDG) are defects in glycoprotein and glycolipid glycan synthesis and attachment. They affect multiple organ/systems, but non-specific symptoms render the diagnosis of the different CDG very challenging. Phosphomannomutase 2 (PMM2)-CDG is the most common CDG, but advances in genetic analysis have shown others to occur more commonly than previously thought. The present work reports the clinical and mutational spectrum of 25 non-PMM2 CDG patients. The most common clinical symptoms were hypotonia (80%), motor or psychomotor disability (80%) and craniofacial dysmorphism (76%). Based on their serum transferrin isoform profile, 18 were classified as CDG-I and 7 as CDG-II. Pathogenic variations were found in 16 genes (ALG1, ALG6, ATP6V0A2, B4GALT1, CCDC115, COG7, DOLK, DPAGT1, DPM1, GFPT1, MPI, PGM1, RFT1, SLC35A2, SRD5A3, and SSR4). Overall, 27 variants were identified, 12 of which are novel. The results highlight the importance of combining genetic and biochemical analyses for the early diagnosis of this heterogeneous group of disorders.

Characterizing Normal and Pathological Gait through Permutation Entropy.

Cerebral palsy is a physical impairment stemming from a brain lesion at perinatal time, most of the time resulting in gait abnormalities: the first cause of severe disability in childhood. Gait study, and instrumental gait analysis in particular, has been receiving increasing attention in the last few years, for being the complex result of the interactions between different brain motor areas and thus a proxy in the understanding of the underlying neural dynamics. Yet, and in spite of its importance, little is still known about how the brain adapts to cerebral palsy and to its impaired gait and, consequently, about the best strategies for mitigating the disability. In this contribution, we present the hitherto first analysis of joint kinematics data using permutation entropy, comparing cerebral palsy children with a set of matched control subjects. We find a significant increase in the permutation entropy for the former group, thus indicating a more complex and erratic neural control of joints and a non-trivial relationship between the permutation entropy and the gait speed. We further show how this information theory measure can be used to train a data mining model able to forecast the child's condition. We finally discuss the relevance of these results in clinical applications and specifically in the design of personalized medicine interventions.

Description of clinical and genetic features of 122 patients included in the Spanish Pompe registry.

Pompe disease is a rare genetic disorder with an estimated prevalence of 1:60.000. The two main phenotypes are Infantile Onset Pompe Disease (IOPD) and Late Onset Pompe Disease (LOPD). There is no published data from Spain regarding the existing number of cases, regional distribution, clinical features or, access and response to the treatment. We created a registry to collect all these data from patients with Pompe in Spain. Here, we report the data of the 122 patients registered including nine IOPD and 113 LOPD patients. There was a high variability in how the diagnosis was obtained and how the follow-up was performed among different centres. Seven IOPD patients were still alive being all treated with enzymatic replacement therapy (ERT) at last visit. Ninety four of the 113 LOPD patients had muscle weakness of which 81 were receiving ERT. We observed a progressive decline in the results of muscle function tests during follow-up. Overall, the Spanish Pompe Registry is a valuable resource for understanding the demographics, patient's journey and clinical characteristics of patients in Spain. Our data supports the development of agreed guidelines to ensure that the care provided to the patients is standardized across the country.

DEVOTE Study Exploring Higher Dose of Nusinersen in Spinal Muscular Atrophy: Study Design and Part A Results.

BACKGROUND: Pharmacokinetic/pharmacodynamic modeling indicates that the higher dose of nusinersen may be associated with a clinically meaningful increase in efficacy above that seen with the 12-mg approved dose. OBJECTIVE: Here we describe both the design of DEVOTE (NCT04089566), a 3-part clinical study evaluating safety, tolerability, and efficacy of higher dose of nusinersen, and results from the initial Part A. METHODS: DEVOTE Part A evaluates safety and tolerability of a higher nusinersen dose; Part B assesses efficacy in a randomized, double-blind design; and Part C assesses safety and tolerability of participants transitioning from the 12-mg dose to higher doses. RESULTS: In the completed Part A of DEVOTE, all 6 enrolled participants aged 6.1-12.6 years have completed the study. Four participants experienced treatment-emergent adverse events (TEAEs), the majority of which were mild. Common TEAEs of headache, pain, chills, vomiting, and paresthesia were considered related to the lumbar puncture procedure. There were no safety concerns regarding clinical or laboratory parameters. Nusinersen levels in the cerebrospinal fluid were within the range of modeled predictions for higher dose of nusinersen. While Part A was not designed for assessing efficacy, most participants showed stabilization or improvement in motor function. Parts B and C of DEVOTE are ongoing. CONCLUSIONS: The findings from Part A of the DEVOTE study support further development of higher dose of nusinersen.

Revisiting genotype-phenotype overlap in neurogenetics: triplet-repeat expansions mimicking spastic paraplegias.

Hereditary spastic paraplegias (HSPs) constitute a heterogeneous group of neurological disorders, characterized primarily by progressive spasticity and weakness of the lower limbs. HSPs are caused by mutations in multiple genes (at least 48 loci and 28 causative genes). The clinical spectrum of HSPs is wide and important differences have been reported between patients with distinct mutations in the same gene, or even between different family members bearing the same mutation. Many patients with HSP present clinical deficits related to the involvement of neuronal systems other than corticospinal tracts, namely, peripheral nerves, sensory, or cerebellar pathways. These cases may be difficult to differentiate from other neurological diseases (e.g., hereditary ataxias), also genetically and clinically heterogeneous. As an illustration of how overlapping this genotype-phenotype relationship is, and the difficulties that it brings upon the development of neurogenetic algorithms and databases, we review the main clinical and genetic features of HSPs, and summarize reports on cases of triplet-repeat spinocerebellar ataxias that can mimic HSP phenotypes. This complex scenario makes the necessity of high-quality, curated mutation databases even more urgent, in order to develop adequate diagnostic guidelines, correct interpretation of genetic testing, and appropriate genetic counseling.

Neurofibromatosis type 1 (NF1) associated with tumor of the corpus callosum.

INTRODUCTION: Neurofibromatosis type 1 (NF1), one of the most common neurocutaneous disorders, is a multisystemic disease associated with tumors in any organ of the body, especially in the central nervous system and also the peripheral nervous system. Pilocytic astrocytomas have been described in almost all intracranial regions in patients with NF1. However, only a few patients with NF1 and tumor of the corpus callosum have been reported to date. MATERIAL AND METHODS: An 11-year-old white Spanish boy was evaluated due to a family history of NF1 and low performance test scores in school. He was studied from the neurological and intellectual level points of view. RESULTS: Magnetic resonance (MR) study revealed a tumor in the anterior-middle portion of the corpus callosum and a Wechsler Intelligence Scale for Children-Revised showed verbal IQ of 92, a performance IQ of 108, and a total IQ of 100. In addition, he showed attention deficit and hyperactivity disorder. CONCLUSIONS: Tumors of corpus callosum in patients with NF1 are very uncommon. The patient presented in this paper consulted due to family history of NF1, progressive hyperactivity, and below average school performance. The MR study showed tumor in the corpus callosum. Tumor histology was not investigated.

Safety and Efficacy of Botulinum Toxin in the Treatment of Self-Biting Behavior in Lesch-Nyhan Disease.

BACKGROUND: Lesch-Nyhan disease (LND) is a disease of purine metabolism linked to chromosome X due to the absence or near-absence of enzyme hypoxanthine-guanine phosphoribosyltransferase. Patients with LND have a compulsive autoaggressive behavior that consists of self-mutilation by biting. METHODS: The objective of this study was to explore the safety and efficacy of botulinum toxin (BoNT) injected into the masticatory muscles and biceps brachii to reduce self-mutilation in patients with LND. We retrospectively analyzed six patients with LND who were treated with BoNT to prevent automutilatory behavior. RESULTS: The patient ages when started on treatment with BoNT were 4, 4.5, 6.6, 7.9, 13.9, and 32.3 years. Patients received a mean number of injections of 20, ranging from 3 to 29, over a period that ranged from 1.5 to 7.1 years. The maximum total dose of Botox was 21.3 units/kg mean and the maximum total dose of Dysport was 37.5 units/kg mean. A total of 119 injections were performed. Of these 113 (95%) were partially or completely effective. Only three of 119 injections (2.5%) produced adverse effects. CONCLUSIONS: Botulinum toxin is useful and safe for the treatment of self-biting behavior in patients with LND.

Scientific rationale for a higher dose of nusinersen.

OBJECTIVE: The long-term favorable safety profile of nusinersen provides an opportunity to consider a higher dose. We report on the relationships between nusinersen cerebrospinal fluid (CSF) exposure, biomarker levels, and clinical efficacy. METHODS: The analyses used data from the CS3A and ENDEAR studies of nusinersen in participants with infantile-onset spinal muscular atrophy (SMA). Steady-state CSF trough (Ctrough ) levels, plasma phosphorylated neurofilament heavy chain (pNF-H) levels, body weight, and Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) scores were selected as parameters of interest. A validated population pharmacokinetic (PK) model was applied to predict the nusinersen CSF Ctrough . PK/pharmacodynamic (PK/PD) models used nusinersen CSF Ctrough measurements, which were time-matched with CHOP INTEND scores. RESULTS: Higher nusinersen CSF exposure was associated with a greater decrease in pNF-H levels and greater efficacy, as measured by change in the CHOP INTEND score from baseline. These findings indicate a dose-response relationship between CSF nusinersen levels and treatment response. The higher dose is predicted to lead to approximately a 2.4-fold increase in nusinersen CSF levels with fewer loading doses. PK/PD modeling indicates that a higher concentration of nusinersen may predict an additional 5-point increase in CHOP INTEND score beyond that observed with 12 mg. INTERPRETATION: Our data indicate that a higher dose of nusinersen may lead to additional clinically meaningful improvement in efficacy when compared with the currently approved 12-mg dose. The efficacy, safety, and PK of a higher nusinersen dose are currently under investigation in the ongoing phase 2/3 DEVOTE study (NCT04089566).

Pascual-Castroviejo type II syndrome (P-CIIS). Importance of the presence of persistent embryonic arteries.

INTRODUCTION: Cutaneous hemangioma and vascular malformation are two vascular abnormalities frequently associated with absence or hypoplasia of one or both carotid and/or vertebral arteries, presence of persistent embryonic arteries, especially the trigeminal, cerebellar malformations, and coarctation of the aortic arch and/or congenital cardiopathy. This disease is known as Pascual-Castroviejo type II syndrome (P-CIIS) and by the acronym PHACE. MATERIAL AND METHODS: Three patients (two females and one male) with facial hemangioma are studied during the first years of age by magnetic resonance angiography (MRA) and their vascular evolution to adult age followed through several MRA controls. RESULTS: All the three patients showed persistence of the trigeminal artery associated to other intra- and extracranial vascular abnormalities of type hemangioma or hemangiomatous arteries that presented progressive involution with decreased arterial caliber without appearing cerebrovascular stroke or hypoxic zones because, at the same time, collateral vascularization appeared through connections between the embryonic arteries and the peripheral branches of the internal carotids or connections between branches of the external and internal carotids. Only one patient had obstruction of a branch of the left middle cerebral artery after 3 days, with gastroenteritis with elevated fever at 17 months of life that caused parenchymal infarct in the left cerebral region supplied by the obstructed artery. CONCLUSIONS: The presence of embryonic arteries, especially the trigeminal, and connections between branches of the internal and external carotids, mainly through the internal maxillary and ophthalmic arteries, ensure the cerebral supply in the P-CIIS despite the progressive involvement of the cerebral arteries.

Visuospatial functions in preterm schoolchildren without cognitive delay: Using Pascual's Graphomotor test as a screening method.

BACKGROUND: Preterm children obtain worse scores in tests that evaluate visuospatial functions. Pascual's graphomotor test (PGMt) assesses maturity in copying drawings in childhood, quickly evaluating the graphomotor aptitude that is a partial aspect of non-verbal intelligence. AIMS: To evaluate visuospatial functions in preterm children compared to full-term children. To assess the capacity of the Pascual graphomotor test (PGMt) to detect visuospatial disorders more specifically than non-verbal intelligence quotient (IQ). STUDY DESIGN AND SUBJECTS: case and control study. CASES: preterm children between 5 and 11 years of age without cognitive delay; controls: full-term children with the same characteristics. For each child clinical history, neurological examination, language-free intelligence test Toni 2 (IQ) and Pascual's graphomotor test (PGMt) were carried out. RESULTS: 135 children were enrolled (59 cases vs. 79 controls). The mean age was 7.4 years. 55% were male. The mean gestational age of cases was 30.5 weeks with 34% extremely preterm. Cases obtained worse mean scores in both tests. The mean IQ scores were: cases 117.4, controls 125.0 (p = 0.004). The mean graphomotor quotient (GQ) scores were statistically and clinically significant (cases 76.8; controls 98.3, p = 0.001). Although we have found a positive correlation between IQ and GQ scores (cc = 0.31 p = 0.01), the differences found in the GQ between groups have been maintained regardless of the IQ in the multivariate analysis (GQ: cases 78.3 (SD 14.8), controls 98.3 (SD 12.5), p = 0.04). CONCLUSIONS: GQ is a useful tool for screening for visuospatial anomalies. GQ more specifically measures the visuoperceptive disorder regardless of non-verbal cognitive level.

The Role of Respiratory Viruses in Children with Ataxia-Telangiectasia.

BACKGROUND: The impact of respiratory virus infection in patients diagnosed with ataxia-telangiectasia (A-T) has not been well studied. METHODS: A prospective case control study was performed at a National Reference Unit for Primary Immunodeficiency in Spain (from November 2018 to July 2019), including patients younger than 20 years. Symptom questionnaires and nasopharyngeal swabs from multiple respiratory viruses' polymerase chain reaction were collected monthly, and between visits in case of symptoms. RESULTS: Twenty-two individuals were included (11 patients; 11 controls); 164 samples were obtained (81 patients; 84 controls). Patients presented respiratory symptoms more frequently compared with controls (26.5% vs. 3.5%; p < 0.01). Viral detection was observed in 23 (27.3%) episodes in patients and in 15 (17.8%) episodes in controls (p = 0.1). Rhinovirus was the most frequent virus in patients and controls (60% and 53.3%, respectively). Episodes with positive viral detection had associated symptoms in 54% of patients and 18% of controls (p = 0.07). However, patients with A-T presented a similar rate of symptoms during episodes with positive and negative viral detection (26% vs. 27%). The median points given for each questionnaire during symptomatic episodes with negative viral detection were 13/23 points, and during symptomatic positive detection, 7.5/23 points (p = 0.1). In the control group, all but two were asymptomatic during positive viral episodes (score: 2/23 and 3/23 points). Symptomatic episodes, with either positive or negative viral detection, were associated with lower IgA and higher IgM titers and higher CD8+ counts (p < 0.05), particularly when these episodes were moderate/severe. CONCLUSIONS: Patients with A-T more frequently present symptomatic viral infections than controls, especially those with lower IgA and higher IgM titers and higher CD8+ counts.

COVID-19 in children with neuromuscular disorders.

OBJECTIVE: Children with neuromuscular disorders have been assumed to be a particularly vulnerable population since the beginning of COVID-19. Although this is a plausible hypothesis, there is no evidence that complications or mortality rates in neuromuscular patients are higher than in the general population. The aim of this study is to describe the clinical characteristics and outcome of COVID-19 in children with neuromuscular disorders. METHODS: A registry of children with neuromuscular conditions and laboratory-confirmed-SARS-CoV-2 infection was set up by the Neuromuscular Working Group of the Spanish Pediatric Neurology Society (SENEP). Data to be collected were focused on the characteristics and baseline status of the neuromuscular condition and the course of COVID-19. RESULTS: Severe complications were not observed in our series of 29 children with neuromuscular disorders infected by SARS-CoV-2. Eighty-nine percent of patients were clinically categorized as asymptomatic or mild cases and 10% as moderate cases. Patients with a relatively more severe course of COVID-19 had SMA type 1 and were between 1 and 3 years. CONCLUSIONS: The course of COVID-19 in children with neuromuscular disorders may not be as severe as expected. The protective role of young age seems to outweigh the risk factors that are common in neuromuscular patients, such as a decreased respiratory capacity or a weak cough. Further studies are needed to know if this finding can be generalized to children with other chronic diseases.

Phenotype variations in early onset Pompe disease: diagnosis and treatment results with Myozyme.

Pompe disease is a rare autosomal recessive lysosomal storage disease caused by deficiency of acid-a-glucosidase (GAA). This deficiency results in glycogen accumulation in the lysosomes, leading to lysosomal swelling, cellular damage and organ dysfunction. Patient age at the onset of Pompe disease symptoms and the rate of deterioration can vary considerably. In early onset patients (the classical infantile form) this glycogen accumulation leads to death usually before the age of 1 year. Some patients with early onset don't develop cardiomyopathy and their progression is slower (atypical infantile form). The late-onset form (juvenile and adult forms) have more slow and variable course. The gene is localized in 17q25. More than 200 different mutations have already been described. Diagnosis has been classically made by mean of muscular biopsy. Nowadays is more convenient the screening of GAA in dried blood sample followed by GAA assessment in lymphocytes or fibroblasts or by the genetic study of mutations. Besides non specific multiprofessional management, since 2006 there is a specific enzyme replacement therapy (ERT), Myozyme), which compensates for the missing enzyme by i.v. administration of recombinant produced enzyme. In classic Pompe disease the reported results improve significantly the survival, the motor development and the cardiac function. The sooner ERT starts, the better are the results. In late onset Pompe disease ERT has also demonstrated significant improvement in muscular function and quality of life.

Clinical guide for the diagnosis and follow-up of myotonic dystrophy type 1, MD1 or Steinert's disease. / Guía clínica para el diagnóstico y seguimiento de la distrofia miotónica tipo 1, DM1 o enfermedad de Steinert.

BACKGROUND AND OBJECTIVES: Steinert's disease or myotonic dystrophy type 1 (MD1), (OMIM 160900), is the most prevalent myopathy in adults. It is a multisystemic disorder with dysfunction of virtually all organs and tissues and a great phenotypical variability, which implies that it has to be addressed by different specialities with experience in the disease. The knowledge of the disease and its management has changed dramatically in recent years. This guide tries to establish recommendations for the diagnosis, prognosis, follow-up and treatment of the complications of MD1. MATERIAL AND METHODS: Consensus guide developed through a multidisciplinary approach with a systematic literature review. Neurologists, pulmonologists, cardiologists, endocrinologists, neuropaediatricians and geneticists have participated in the guide. RECOMMENDATIONS: The genetic diagnosis should quantify the number of CTG repetitions. MD1 patients need cardiac and respiratory lifetime follow-up. Before any surgery under general anaesthesia, a respiratory evaluation must be done. Dysphagia must be screened periodically. Genetic counselling must be offered to patients and relatives. CONCLUSION: MD1 is a multisystemic disease that requires specialised multidisciplinary follow-up.

Sturge-Weber syndrome: study of 55 patients.

PURPOSE: To review the clinical and neuroimaging features of a large series of patients with Sturge-Weber syndrome (SWS) seen over a 40-year period. METHODS: Fifty-five patients with SWS (30 males and 25 females), were studied between 1965 and 2004. Results of neurological and ophthalmological examinations, electroencephalographic, and neuroimaging studies were reviewed. All patients were seen by one of the authors (I. P-C). RESULTS: Epilepsy, hemiparesis, mental retardation and ocular problems were the most frequent and severe features of patients with Sturge-Weber syndrome in this series. The facial nevus flammeus was unilateral in 35 (63.5%) patients, bilateral in 17 (31%) and absent in 3 (5.5%) of the patients with leptomeningeal angiomas. Seven (41%) of the 17 patients with bilateral nevus flammeus had unilateral leptomeningeal angiomas. Seizures occurred in 47 patients (85.5%). Complete seizure control was obtained in 20 patients (42.5%), but in 2 of these 20 patients seizures were controlled only after lobectomy. All patients with unilateral or bilateral upper eyelid nevus flammeus had ipsilateral, unilateral or bilateral choroid-retinal angiomas. Only 20 (36%) of the 55 patients had low-normal or borderline intelligence (IQs < 70). No relationship was observed between the size of the facial nevus flammeus and the severity of the brain lesion. CONCLUSIONS: Epilepsy, hemiparesis, mental retardation and ocular problems were the most frequent and severe features of patients with Sturge-Weber syndrome in this series. Cerebral lesions followed a progressive course during early childhood, but not later. Early surgical treatment controlled the seizures but other neurological problems such as hemiparesis and intellectual deficits showed a less satisfactory response. Early onset of seizures and poor response to medical treatment, bilateral cerebral involvement and unilateral severe lesions were indicative of a poor prognosis. Limited intelligence and social skills, poor aesthetic appearance and seizures complicated the integration of SWS patients. These features must be addressed in order for the patients improve social interactions, obtain gainful employment and achieve a better quality of life.

Generation of human induced pluripotent stem cell (iPSC) line from an unaffected female carrier of mutation in SACSIN gene.

The human iPSC cell line, CARS-FiPS4F1 (ESi064-A), derived from dermal fibroblast from the apparently healthy carrier of the mutation of the gene SACSIN, was generated by non-integrative reprogramming technology using OCT3/4, SOX2, CMYC and KLF4 reprogramming factors. The pluripotency was assessed by immunocytochemistry and RT-PCR. This iPSC line can be used as control for Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) disease.

Generation of a human iPSC line from a patient with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) caused by mutation in SACSIN gene.

The human iPSC cell line, ARS-FiPS4F1 (ESi063-A), derived from dermal fibroblast from the patient autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) caused by mutations on the gene SACSIN, was generated by non-integrative reprogramming technology using OCT3/4, SOX2, CMYC and KLF4 reprogramming factors. The pluripotency was assessed by immunocytochemistry and RT-PCR. Differentiation capacity was verified in vitro. This iPSC line can be further differentiated toward affected cells to better understand molecular mechanisms of disease and pathophysiology.

Gait phenotypes in paediatric hereditary spastic paraplegia revealed by dynamic time warping analysis and random forests.

The Hereditary Spastic Paraplegias (HSP) are a group of heterogeneous disorders with a wide spectrum of underlying neural pathology, and hence HSP patients express a variety of gait abnormalities. Classification of these phenotypes may help in monitoring disease progression and personalizing therapies. This is currently managed by measuring values of some kinematic and spatio-temporal parameters at certain moments during the gait cycle, either in the doctor´s surgery room or after very precise measurements produced by instrumental gait analysis (IGA). These methods, however, do not provide information about the whole structure of the gait cycle. Classification of the similarities among time series of IGA measured values of sagittal joint positions throughout the whole gait cycle can be achieved by hierarchical clustering analysis based on multivariate dynamic time warping (DTW). Random forests can estimate which are the most important isolated parameters to predict the classification revealed by DTW, since clinicians need to refer to them in their daily practice. We acquired time series of pelvic, hip, knee, ankle and forefoot sagittal angular positions from 26 HSP and 33 healthy children with an optokinetic IGA system. DTW revealed six gait patterns with different degrees of impairment of walking speed, cadence and gait cycle distribution and related with patient's age, sex, GMFCS stage, concurrence of polyneuropathy and abnormal visual evoked potentials or corpus callosum. The most important parameters to differentiate patterns were mean pelvic tilt and hip flexion at initial contact. Longer time of support, decreased values of hip extension and increased knee flexion at initial contact can differentiate the mildest, near to normal HSP gait phenotype and the normal healthy one. Increased values of knee flexion at initial contact and delayed peak of knee flexion are important factors to distinguish GMFCS stages I from II-III and concurrence of polyneuropathy.