Adult Autism Subthreshold Spectrum (AdAS Spectrum): Validation of a questionnaire investigating subthreshold autism spectrum.

AIM: Increasing literature has shown the usefulness of a dimensional approach to autism. The present study aimed to determine the psychometric properties of the Adult Autism Subthreshold Spectrum (AdAS Spectrum), a new questionnaire specifically tailored to assess subthreshold forms of autism spectrum disorder (ASD) in adulthood. METHODS: 102 adults endorsing at least one DSM-5 symptom criterion for ASD (ASDc), 143 adults diagnosed with a feeding and eating disorder (FED), and 160 subjects with no mental disorders (CTL), were recruited from 7 Italian University Departments of Psychiatry and administered the following: SCID-5, Autism-Spectrum Quotient (AQ), Ritvo Autism and Asperger Diagnostic Scale 14-item version (RAADS-14), and AdAS Spectrum. RESULTS: The AdAS Spectrum demonstrated excellent internal consistency for the total score (Kuder-Richardson's coefficient=.964) as well as for five out of seven domains (all coefficients>.80) and sound test-retest reliability (ICC=.976). The total and domain AdAS Spectrum scores showed a moderate to strong (>.50) positive correlation with one another and with the AQ and RAADS-14 total scores. ASDc subjects reported significantly higher AdAS Spectrum total scores than both FED (p<.001) and CTL (p<.001), and significantly higher scores on the Childhood/adolescence, Verbal communication, Empathy, Inflexibility and adherence to routine, and Restricted interests and rumination domains (all p<.001) than FED, while on all domains compared to CTL. CTL displayed significantly lower total and domain scores than FED (all p<.001). A significant effect of gender emerged for the Hyper- and hyporeactivity to sensory input domain, with women showing higher scores than men (p=.003). A Diagnosis* Gender interaction was also found for the Verbal communication (p=.019) and Empathy (p=.023) domains. When splitting the ASDc in subjects with one symptom criterion (ASD1) and those with a ASD, and the FED in subjects with no ASD symptom criteria (FED0) and those with one ASD symptom criterion (FED1), a gradient of severity in AdAS Spectrum scores from CTL subjects to ASD patients, across FED0, ASD1, FED1 was shown. CONCLUSIONS: The AdAS Spectrum showed excellent internal consistency and test-retest reliability and strong convergent validity with alternative dimensional measures of ASD. The questionnaire performed differently among the three diagnostic groups and enlightened some significant effects of gender in the expression of autistic traits.

CMT subtypes and disease burden in patients enrolled in the Inherited Neuropathies Consortium natural history study: a cross-sectional analysis.

BACKGROUND: The international Inherited Neuropathy Consortium (INC) was created with the goal of obtaining much needed natural history data for patients with Charcot-Marie-Tooth (CMT) disease. We analysed clinical and genetic data from patients in the INC to determine the distribution of CMT subtypes and the clinical impairment associated with them. METHODS: We analysed data from 1652 patients evaluated at 13 INC centres. The distribution of CMT subtypes and pathogenic genetic mutations were determined. The disease burden of all the mutations was assessed by the CMT Neuropathy Score (CMTNS) and CMT Examination Score (CMTES). RESULTS: 997 of the 1652 patients (60.4%) received a genetic diagnosis. The most common CMT subtypes were CMT1A/PMP22 duplication, CMT1X/GJB1 mutation, CMT2A/MFN2 mutation, CMT1B/MPZ mutation, and hereditary neuropathy with liability to pressure palsy/PMP22 deletion. These five subtypes of CMT accounted for 89.2% of all genetically confirmed mutations. Mean CMTNS for some but not all subtypes were similar to those previously reported. CONCLUSIONS: Our findings confirm that large numbers of patients with a representative variety of CMT subtypes have been enrolled and that the frequency of achieving a molecular diagnosis and distribution of the CMT subtypes reflects those previously reported. Measures of severity are similar, though not identical, to results from smaller series. This study confirms that it is possible to assess patients in a uniform way between international centres, which is critical for the planned natural history study and future clinical trials. These data will provide a representative baseline for longitudinal studies of CMT. CLINICAL TRIAL REGISTRATION: ID number NCT01193075.

POMT1 and POMT2 mutations in CMD patients: a multicentric Italian study.

Mutations in POMT1 and POMT2 genes were originally identified in Walker-Warburg syndrome (WWS) and subsequently reported in patients with milder phenotypes characterised by mental retardation with or without brain abnormalities and without ocular malformations. As part of a multicentric Italian study we screened the POMT1 and POMT2 genes in 61 congenital muscular dystrophy (CMD) patients with alpha-dystroglycan reduction on muscle biopsy and/or clinical and radiological findings suggestive of the known forms of CMD with alpha-dystroglycan deficiency. The aim of the study was to establish how frequently mutations in POMT1 and POMT2 occur in CMD patients in the Italian population and to evaluate the spectrum of associated phenotypes. Thirteen patients showed mutations in POMT1 and five harboured mutations in POMT2, accounting for a total of 20 different mutations, eight of which were novel (two in POMT1 and six in POMT2). Normal brain MRI associated with mental retardation and microcephaly was the most frequent finding in patients with mutations in POMT1 (six out of 13), but was also found in a patient with POMT2 mutations. Predominant cerebellar hypoplasia was also frequent both in patients with POMT1 (three out of 13) and POMT2 (three out of 5) mutations. A MEB phenotype with frontal cortical dysplasia and pons abnormalities was found in two patients with POMT1 and in one with POMT2 mutations, while a WWS phenotype was only found in a case with mutations in POMT1. Mutations causing frameshifts and stop codons were responsible for the more severe phenotypes. Our results provide further evidence that, as previously reported for FKRP, the array of mutations in POMT1 and POMT2 is ample and the spectrum of associated phenotypes is wider than initially thought.

Intrafamilial phenotypic variability in Andersen-Tawil syndrome: A diagnostic challenge in a potentially treatable condition.

Andersen-Tawil syndrome (ATS) is a rare autosomal dominant channelopathy characterized by periodic paralysis, cardiac dysrhythmias, and distinct facial and skeletal characteristics, that may be variably present in the affected members. Mutations in the KCNJ2 and KCNJ5 gene have been associated with this disorder. We describe a family in which several members presented with different ATS phenotypes. The proband, a 4-year-old boy, presented with recurrent episodes of muscle weakness from an early age; two siblings suffered cardiac arrhythmia but had never experienced episodes of paralysis; their mother reported occasional muscle pain after exercise and unspecified cardiac arrhythmias. The analysis of KCNJ2 gene in the proband disclosed the presence of a pathogenic mutation (p.R218W), that was subsequently confirmed in the other affected subjects. Our results underline the possible intrafamilial phenotypic variability, ranging from full clinical triad to exclusive cardiac or muscular involvement, representing a diagnostic challenge that may also delay adequate management. There are still limited data on the treatment of ATS; in our patient there was clinical improvement with dichlorphenamide.

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". We distinguished patients with ocular myopathy as part of a multisystem mitochondrial encephalomyopathy (PEO-encephalomyopathy), and then PEO with isolated ocular myopathy from PEO-plus when PEO was associated with additional features of multisystemic involvement. Ocular myopathy was the most common feature in our cohort of mitochondrial patients. Among the 722 patients with a definite genetic diagnosis, ocular myopathy was observed in 399 subjects (55.3%) and was positively associated with mtDNA single deletions and POLG mutations. Ocular myopathy as manifestation of a multisystem mitochondrial encephalomyopathy (PEO-encephalomyopathy, n = 131) was linked to the m.3243A>G mutation, whereas the other "PEO" patients (n = 268) were associated with mtDNA single deletion and Twinkle mutations. Increased lactate was associated with central neurological involvement. We then defined, among the PEO group, as "pure PEO" the patients with isolated ocular myopathy and "PEO-plus" those with ocular myopathy and other features of neuromuscular and multisystem involvement, excluding central nervous system. The male proportion was significantly lower in pure PEO than PEO-plus. This study reinforces the need for research on the role of gender in mitochondrial diseases. The phenotype definitions here revisited may contribute to a more homogeneous patient categorization, useful in future studies and clinical trials.

Clinical and molecular findings in children with complex I deficiency.

Isolated complex I deficiency, the most frequent OXPHOS disorder in infants and children, is genetically heterogeneous. Mutations have been found in seven mitochondrial DNA (mtDNA) and eight nuclear DNA encoded subunits, respectively, but in most of the cases the genetic basis of the biochemical defect is unknown. We analyzed the entire mtDNA and 11 nuclear encoded complex I subunits in 23 isolated complex I-deficient children, classified into five clinical groups: Leigh syndrome, progressive leukoencephalopathy, neonatal cardiomyopathy, severe infantile lactic acidosis, and a miscellaneous group of unspecified encephalomyopathies. A genetic definition was reached in eight patients (35%). Mutations in mtDNA were found in six out of eight children with Leigh syndrome, indicating a prevalent association between this phenotype and abnormalities in ND genes. In two patients with leukoencephalopathy, homozygous mutations were detected in two different nuclear-encoded complex I genes, including a novel transition in NDUFS1 subunit. In addition to these, a child affected by mitochondrial encephalomyopathy had heterozygous mutations in NDUFA8 and NDUFS2 genes, while another child with neonatal cardiomyopathy had a complex rearrangement in a single NDUFS7 allele. The latter cases suggest the possibility of unconventional patterns of inheritance in complex I defects.

Non-coding VMA21 deletions cause X-linked myopathy with excessive autophagy.

X-linked Myopathy with Excessive Autophagy (XMEA) affects proximal muscles of the lower extremities and follows a progressive course reminiscent of muscular dystrophy. It is caused by mutations in VMA21 whose protein product assembles lysosomes' proton pumps. All XMEA mutations to date have been single-nucleotide substitutions that reduce VMA21 expression, which leads to modest lysosomal pH increase, the first step in the disease's pathogenesis. We now report a new class of XMEA mutations. We identified two VMA21 non-coding microdeletions, one intronic (c.54-16_54-8del), the other in the 3'UTR (c.*13_*104del). Both resulted in a relatively more severe (early ambulation loss), diffuse (extra-ocular and upper extremity involvement), and early (neonatal) onset disease compared to previously reported patients. Our cases highlight the importance of including non-coding regions of VMA21 in genetic testing panels of dystrophies and myopathies. Specific diagnosis of XMEA will be particularly important as therapies aimed at correcting the modest rise in lysosomal pH at the root of this disease are developed.

Mild clinical phenotype in a 12-year-old boy with partial merosin deficiency and central and peripheral nervous system abnormalities.

We found partial merosin deficiency in a boy presenting at 12 yr with marked limb weakness and a waddling gait. Magnetic resonance imaging (MRI) showed the characteristic white matter abnormalities of merosin-negative congenital muscular dystrophy. There were also peripheral demyelinating polyneuropathy and evoked potential abnormalities. Unlike classic merosin-negative congenital muscular dystrophy, however, our patient was less hypotonic and weak and was able to achieve independent walking. Both by immunohistochemistry and Western blot merosin was shown to be moderately reduced. By immunostaining the alpha 1 laminin chain was overexpressed and beta 1 laminin chain was reduced. A spectrum of clinical phenotypes is likely to become evident in merosin-deficient patients in relation to the discovery of a range of molecular defects in, and variable expression of, this protein.

Ryanodine receptor gene point mutation and malignant hyperthermia susceptibility.

Malignant hyperthermia (MH) is a rare clinical syndrome, triggered in susceptible subjects by a variety of anaesthetic agents and muscle relaxants, and is the commonest cause of death due to general anaesthesia. Previous studies have reported that inherited mutations in the ryanodine receptor (RYR1) gene co-segregated, in some families, with MH susceptibility; lack of linkage between MH and the RYR1 gene in some other families indicates a heterogenous genetic basis for the syndrome. The in vitro contracture test (IVCT) on muscle biopsy specimens is considered to be the most reliable test for establishing the diagnosis of MH. With the identification of RYR1 point mutations this might in turn result in non-invasive methods for the presymptomatic diagnosis of MH. In the present study we investigated four families suspected to be at risk of MH susceptibility; in all subjects histopathological examination and IVCT were performed on muscle biopsy specimens. We undertook a mutation analysis of RYR1 gene testing for the presence of five point mutations; in one pedigree a C1840-->T point mutation was detected, strictly segregating with in vitro MH susceptibility.

Ubidecarenone in the treatment of mitochondrial myopathies: a multi-center double-blind trial.

Forty-four patients with mitochondrial myopathies were treated with Ubidecarenone (CoQ10) for 6 months in an open multi-center trial. No side effects of the drug were observed. Sixteen patients showing at least 25% decrease of post-exercise lactate levels were selected as responders. Responsiveness was apparently not related to CoQ10 level in serum and platelets or to the presence or absence of mtDNA deletions. The responders were treated for a further 3 months with CoQ10 or placebo in the second blind part of the trial; no significant differences were observed between the 2 groups. It is not clear why CoQ10 had therapeutic effects in some patients and not in others with the same clinical presentation and biochemical defect, and we failed to identify candidate responders before treatment. At the dose of CoQ10 used in this study (2 mg/kg/day) the therapy requires a long administration time before a response is seen.

Riboflavin-responsive glutaric aciduria type II presenting as a leukodystrophy.

The clinical phenotype of multiple acyl-CoA dehydrogenase deficiency in infancy is characterized by recurrent episodes of hypoketotic hypoglycemia and lipid storage myopathy. Brain damage has been described only as a consequence of severe and protracted hypoglycemia. We describe a child who experienced normal physical and psychomotor development until the age of 3 years, who then developed progressive intention tremors, dysarthria, ataxia, and spastic tetraparesis. Episodes of acute metabolic distress were never observed. Magnetic resonance imaging disclosed abnormal signals within the white matter of the brain and cerebellum, suggesting leukodystrophy. Gas chromatography/mass spectrometry analysis revealed abnormally high levels of glutaric acid, dicarboxylic acids, and glycine derivatives in urine. Riboflavin therapy was initiated at 4 years of age, when the patient had already lost control of trunk and head posture. Consistent improvement rapidly occurred after riboflavin supplementation. Glutaric aciduria type II may cause brain damage, in spite of the absence of acute metabolic distress, and should be considered in the differential diagnosis of leukodystrophies.

Costello syndrome: a cancer predisposing syndrome?

Costello Syndrome is a specific MCA/MR syndrome mainly characterized by dysmorphic facial features, peculiar biphasic growth pattern, motor and mental retardation, ectodermal anomalies involving skin and nails, and age dependent development of nasal and perianal papillomata. Heart malformations and/or hypertrophic cardiomyopathy are frequently observed. We report a 4-year-old girl with Costello syndrome who developed an intrathoracic ganglioneuroblastoma. In previous reports two patients with ectodermal tumours have been described, a ganglioneuroblastoma of the adrenal gland and an epithelioma. This third report suggests that neural crest neoplasia may be a significant risk factor for children with Costello syndrome.

Multicenter trial with ubidecarenone: treatment of 44 patients with mitochondrial myopathies.

Fourty four patients with mitochondrial myopathies were treated with Ubidecarenone (CoQ10) for six months in an open multicentric trial. No side effects due to the drug administration were observed. Sixteen patients showing at least 25% decrease of post exercise lactate levels were selected as responders. Responsiveness was apparently not related to CoQ10 level in serum and platelets or to the presence or absence of mtDNA deletions. The responders were further treated for 3 months with CoQ10 or placebo in the second blind part of the trial; no significant differences between the 2 groups were observed. It is not clear why CoQ10 had therapeutic effects in some patients and not in others with the same clinical presentation and biochemical defect, and we failed to identify candidate responders before treatment. At the dosage of CoQ10 used in the study (2 mg/kg/day) the therapy requires long administration time before a response is demonstrable.

Mitochondrial Diseases in Childhood.

Mitochondrial disorders are a group of heterogeneous diseases associated with abnormalities of the oxidative phosphorylation (OXPHOS), the most important source of energy for the cell. The number of mitochondrial syndromes and of identified causative genes is constantly increasing. Taken as a whole they are among the most frequent genetic diseases in humans at any age. The respiratory chain is the only metabolic pathway under double genome control and molecular genetics of these disorders is complicated by the existence of strict interactions between mitochondrial DNA and nuclear DNA. In childhood and infancy, clinical presentation differs from mitochondrial disorders with adult onset. The phenotypes are much more severe, often involving brain, frequently presenting as multisystemic disorders and seldom as isolated myopathy. Mutations in nDNA are more frequent than in adulthood. The major phenotypes presenting in infancy are here correlated with genetic defects and biochemical data with the aim to facilitate diagnosis work-up.

A fourth case of POMT2-related limb girdle muscle dystrophy with mild reduction of α-dystroglycan glycosylation.

BACKGROUND: POMT2 mutations have been identified in Walker-Warburg syndrome or muscle-eye-brain-like, but rarely in limb girdle muscular dystrophy (LGMD). RESULTS: Two POMT2 mutations, one null and one missense, were found in a patient with LGMD and mild mental impairment, no brain or ocular involvement, minor histopathological features, and slight reduction of α-dystroglycan (α-DG) glycosylation and α-DG laminin binding. CONCLUSIONS: Our case, the fourth LGMD POMT2-mutated reported to date, provides further evidence of correlation between level of α-DG glycosylation and phenotype severity.

Gait pattern classification in children with Charcot-Marie-Tooth disease type 1A.

Gait pattern classification may assist in clinical decision making and cluster analysis (CA) has been often adopted to this aim. The goal of this study was to identify, through CA, typical walking patterns in a group of 21 young subjects with CMT1A, a hereditary progressive neuropathy, and to study possible correlation with the disease's clinical status. The protocol included kinematic/kinetic analysis of natural walking and more demanding locomotor tasks, i.e. toe- and heel-walking. Hierarchical cluster analysis was carried out on parameters related to primary signs (foot-drop and push-off deficit) and, separately, to compensatory mechanisms at proximal (pelvis, hip and knee) or distal (ankle) level. CA on primary signs during natural walking identified three clusters: (1) pseudo-normal patients (PN), not significantly different from controls; (2) patients showing only foot-drop (FD); (3) patients with foot-drop and push-off deficit (FD&POD). Patients belonging to the PN subgroup showed distal abnormalities during heel-walking. The FD&POD subgroup was associated to a significantly worse clinical score (CMTES, p<0.05). The main compensatory strategies, which occurred independently from primary clusterization, included augmented hip/knee flexion in swing (steppage) and early ankle plantarflexion at mid stance (vaulting). We concluded that, although a number of young CMT1A patients do not show typical primary deviations during natural walking, they do show significant abnormalities in more demanding locomotor tasks that should be therefore considered. It is also hypothesized that progression of this degenerative condition may be associated to the migration of patients to more severe clusters, with possible appearance of compensatory strategies.

Novel POMGNT1 point mutations and intragenic rearrangements associated with muscle-eye-brain disease.

Congenital muscular dystrophies due to defects in genes encoding proteins involved in α-dystroglycan (α-DG) glycosylation are a heterogeneous group of muscle disorders variably associated with central nervous system and eye abnormalities. One of the more severe is muscle-eye-brain disease (MEB). Mutations in genes coding for proven or putative glycosyltransferases (POMT1, POMT2, POMGnT1, fukutin, FKRP, and LARGE), the DPM3 gene encoding a DOL-P-Man synthase subunit, and the DAG1 gene encoding α-dystroglycan, have been associated with altered α-DG glycosylation. We report new POMGnT1 mutations and evaluate protein expression in 3 patients and 2 foetuses with variably severe MEB features. We identify two new point mutations (c.643C>T, c.1863delC), one new intragenic rearrangement (deletion of exons 2-8), and a new intron retention (between exons 21 and 22) resulting from a known point mutation c.1895+1G>T. Our study provides further evidence that rearrangements of the POMGnT1 gene are relatively common. Importantly, if heterozygous, they can be missed on standard genomic DNA sequencing. POMGNT1 protein analysis in 3 patients showed that the severity of the phenotype does not correlate with protein expression. Cerebral MRI is important for identifying MEB and α-dystroglycanopathy phenotypes in children and foetuses, and hence for directing the genetic analysis.

Respiratory and cardiac function in congenital muscular dystrophies with alpha dystroglycan deficiency.

The aim of this retrospective study was to assess respiratory and cardiac function in a large cohort of patients with congenital muscular dystrophies (CMD) with reduced glycosylation of alphadystroglycan (α-DG). Thirteen of the 115 patients included in the study died between the age of 1 month and 20 years. The age at last follow up of the surviving 102 ranged between 1 year and 68 years (median: 9.3 years). Cardiac involvement was found in 7 of the 115 (6%), 5 with dilated cardiomyopathy, 1 cardiac conductions defects and 1 mitral regurgitation. Respiratory function was impaired in 14 (12%). Ten of the 14 required non invasive nocturnal respiratory support, while the other four required invasive ventilation. Cardiac or respiratory involvement was found in patients with mutations in FKRP, POMT1, POMT2. All of the patients in whom mutation in POMGnT1 were identified had normal cardiac and respiratory function.

Reliability of instrumented movement analysis as outcome measure in Charcot-Marie-Tooth disease: results from a multitask locomotor protocol.

Some neurodegenerative diseases at early stage may not drastically affect basic gait ability, whereas more demanding locomotor tasks are more prone to disease-induced abnormalities. In this study, we evaluated the interday test-retest reliability, 4-6 weeks apart, of instrumented movement analysis on a group of 20 subjects with Charcot-Marie-Tooth (CMT) disease considering a set of kinematic and kinetic curves and related parameters obtained during natural walking (NW) and faster walking, heel and toe-walking, step ascending and descending. Results showed that the reliability was good for NW, with the exception of trunk curves, pelvic tilt and EMG profiles (moderate reliability), and trunk ROM in sagittal/transverse plane (poor reliability). Comparing our results with literature, CMT patients did not present a greater variability during NW than healthy subjects or patients with diseases of CNS. Additional locomotor tasks showed a slight reduction of reliability, although the moderate-to-good level shown in NW was almost never reduced to poor. Most of SEM values (absolute measurement errors) were smaller than 5°, a clinically acceptable threshold. In particular THS, an ankle joint related parameter computed across heel and toe-walking tasks, showed an optimal reliability (ICC=0.95, SEM=2.7°) and correlation with CMT clinical scores. Toe and heel-walking and step ascending tasks maximised the number of parameters with a moderate-to-good correlation with patients' clinical status. We concluded that, in addition to natural walking, more challenging locomotor tasks are good candidates to provide reliable and sensitive outcome measures for CMT patients.

Congenital muscular dystrophies with cognitive impairment. A population study.

BACKGROUND: Cognitive impairment has been reported in a significant proportion of patients with congenital muscular dystrophies (CMD), generally associated with brain changes. OBJECTIVES: The aim of this study was to establish 1) the overall prevalence of CMD and cognitive impairment in the Italian population; 2) the frequency of individual genetically defined forms; and 3) the presence of distinct phenotypes not associated with mutations in the known genes. METHODS: We included all patients with CMD and cognitive impairment followed in all the Italian tertiary neuromuscular centers. Clinical, brain MRI, and morphologic data were collected. Genetic screening of the known genes was performed according to clinical and muscle biopsy findings. RESULTS: Ninety-two of the 160 (58%) patients with CMD followed in our centers had cognitive impairment. alpha-Dystroglycan (alpha-DG) reduction on muscle biopsy was found in 73/92 (79%), with 42/73 carrying mutations in the known genes. Another 6/92 (7%) showed a laminin alpha2 deficiency on muscle biopsy and 5 of the 6 carried mutations in LAMA2. The remaining 13/92 (14%) patients had normal alpha-DG and laminin alpha2 expression on muscle. CONCLUSIONS: This is the first population study establishing the prevalence of CMD and cognitive impairment and providing a classification on the basis of clinical, MRI, and genetic findings. We also showed that cognitive impairment was not always associated with alpha-DG or laminin alpha2 reduction or with structural brain changes.