A new family with an SLC9A6 mutation expanding the phenotypic spectrum of Christianson syndrome.

Using targeted next generation sequencing, we have identified a splicing mutation (c.526-9_526-5del) in the SLC9A6 gene in a 9-year-old boy with mild intellectual disability (ID), microcephaly, and social interaction disabilities. This intronic microdeletion leads to the skipping of exon 3 and to an in-frame deletion of 26 amino acids in the TM4 domain. It segregates with cognitive impairment or learning difficulties in other members of the family. Mutations in SLC9A6 have been reported in X-linked Christianson syndrome associating severe to profound intellectual deficiency and an Angelman-like phenotype with microcephaly, absent speech, ataxia with progressive cerebellar atrophy, ophthalmoplegia, epilepsy, and neurological regression. The proband and his maternal uncle both have an attenuated phenotype with mild ID, attention deficit disorder, speech difficulties, and mild asymptomatic cerebellar atrophy. The proband also have microcephaly. The mutation cosegregated with learning disabilities and speech difficulties in the female carriers (mother and three sisters of the proband). Detailed neuropsychological, speech, and occupational therapy investigations in the female carriers revealed impaired oral and written language acquisition, with dissociation between verbal and performance IQ. An abnormal phenotype, ranging from learning disability with predominant speech difficulties to mild intellectual deficiency, has been described previously in a large proportion of female carriers. Besides broadening the clinical spectrum of SLC9A6 gene mutations, we present an example of a monogenic origin of mild learning disability. © 2016 Wiley Periodicals, Inc.

Intragenic CAMTA1 rearrangements cause non-progressive congenital ataxia with or without intellectual disability.

BACKGROUND: Non-progressive congenital ataxias (NPCA) with or without intellectual disability (ID) are clinically and genetically heterogeneous conditions. As a consequence, the identification of the genes responsible for these phenotypes remained limited. OBJECTIVE: Identification of a new gene responsible for NPCA and ID. Methods Following the discovery of three familial or sporadic cases with an intragenic calmodulin-binding transcription activator 1 (CAMTA1) rearrangement identified by an array-CGH and recruited from a national collaboration, the authors defined the clinical and molecular characteristics of such rearrangements, and searched for patients with point mutations by direct sequencing. RESULTS: Intragenic copy number variations of CAMTA1 were all located in the CG-1 domain of the gene. It segregated with autosomal dominant ID with non-progressive congenital cerebellar ataxia (NPCA) in two unrelated families, and was de novo deletion located in the same domain in a child presenting with NPCA. In the patients with ID, the deletion led to a frameshift, producing a truncated protein, while this was not the case for the patient with isolated childhood ataxia. Brain MRI of the patients revealed a pattern of progressive atrophy of cerebellum medium lobes and superior vermis, parietal lobes and hippocampi. DNA sequencing of the CG-1 domain in 197 patients with sporadic or familial non-syndromic intellectual deficiency, extended to full DNA sequencing in 50 patients with ID and 47 additional patients with childhood ataxia, identified no pathogenic mutation. CONCLUSION: The authors have evidence that loss-of-function of CAMTA1, a brain-specific calcium responsive transcription factor, is responsible for NPCA with or without ID. Accession numbers CAMTA1 reference sequence used was ENST00000303635. Protein sequence was ENSP00000306522.

Care management in a French cohort with Down syndrome from the AnDDI-Rares/CNSA study.

Down syndrome (DS) is a genetic neurodevelopmental disorder. In individuals with DS, a multidisciplinary approach to care is required to prevent multiple medical complications. The aim of this study was to describe the rehabilitation, medical care, and educational and social support provided to school-aged French DS patients with varying neuropsychological profiles. A mixed study was conducted. Quantitative data were obtained from a French multicentre study that included patients aged 4-20 years with diverse genetic syndromes. Qualitative data were collected by semi-structured face-to-face interviews and focus groups. Ninety-five DS subjects with a mean age of 10.9 years were included. Sixty-six per cent had a moderate intellectual disability (ID) and 18.9% had a severe ID. Medical supervision was generally multidisciplinary but access to medical specialists was often difficult. In terms of education, 94% of children under the age of six were in typical classes. After the age of 15, 75% were in medico-social institutions. Analysis of multidisciplinary rehabilitation conducted in the public and private sectors revealed failure to access physiotherapy, psychomotor therapy and occupational therapy, but not speech therapy. The main barrier encountered by patients was the difficulty accessing appropriate facilities due to a lack of space and long waiting lists. In conclusion, children and adolescents with DS generally received appropriate care. Though the management of children with DS has been improved considerably, access to health facilities remains inadequate.

Associations between cognitive performance and the rehabilitation, medical care and social support provided to French children with Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is a rare genetic neurodevelopmental disorder with a characteristic behavioural phenotype. A multidisciplinary approach to care is required to prevent multiple medical complications in individuals affected by PWS. The aim of this study was to describe the rehabilitation, medical care, educational and social support provided to school-aged French PWS patients with varying neuropsychological profiles. Data were obtained from a French multicentre study that included patients aged 4-20 years with diverse genetic syndromes. Nineteen PWS subjects with a mean age of 9.2 years were included. The mean full-scale intellectual quotient (IQ) was 58 (Wechsler scale). There were frequent dissociations between verbal and performance IQ that were not associated with a specific profile. We also observed lower autonomy and communication scores (5.3 years and 5.9 years equivalent, respectively, Vineland scale), the absence of hyperactivity (Conners scale), and the presence of behavioural abnormalities (CBCL scale). Multidisciplinary medical supervision was generally coordinated by the paediatric endocrinologist and did not always include follow-up with all of the recommended specialists, in particular with a paediatric psychiatrist. Analysis of multidisciplinary rehabilitation conducted in public and private-sector establishment revealed failings in psychological support, occupational therapy and dietary follow-up. Regarding education, most children younger than 10 years were in normal schools, while older individuals were often cared for in medico-social institutions. In conclusion, children and adolescents with PWS generally received appropriate care. Though there have been considerable improvements in the management of children with PWS, reference centres should continue reinforcing the coordination of multidisciplinary supervision.

Heterozygous deletion of the LRFN2 gene is associated with working memory deficits.

Learning disabilities (LDs) are a clinically and genetically heterogeneous group of diseases. Array-CGH and high-throughput sequencing have dramatically expanded the number of genes implicated in isolated intellectual disabilities and LDs, highlighting the implication of neuron-specific post-mitotic transcription factors and synaptic proteins as candidate genes. We report a unique family diagnosed with autosomal dominant learning disability and a 6p21 microdeletion segregating in three patients. The 870 kb microdeletion encompassed the brain-expressed gene LRFN2, which encodes for a synaptic cell adhesion molecule. Neuropsychological assessment identified selective working memory deficits, with borderline intellectual functioning. Further investigations identified a defect in executive function, and auditory-verbal processes. These data were consistent with brain MRI and FDG-PET functional brain imaging, which, when compared with controls, revealed abnormal brain volume and hypometabolism of gray matter structures implicated in working memory. We performed electron microscopy immunogold labeling demonstrating the localization of LRFN2 at synapses of cerebellar and hippocampal rat neurons, often associated with the NR1 subunit of N-methyl-D-aspartate receptors (NMDARs). Altogether, the combined approaches imply a role for LRFN2 in LD, specifically for working memory processes and executive function. In conclusion, the identification of familial cases of clinically homogeneous endophenotypes of LD might help in both the management of patients and genetic counseling for families.

Neuropsychological and neuroimaging phenotype induced by a CAMTA1 mutation.

BACKGROUND/AIMS: CAMTA1 mutations have recently been reported in families with intellectual disability and/or non-progressive congenital ataxias. The objective of this study was to describe the neuropsychological and neuroimaging phenotype of CAMTA1 mutation. METHODS: We performed neuropsychological examinations, MRI and FDG-PET imaging in three patients with autosomal dominant mild intellectual disabilities and ataxia induced by a CAMTA1 intragenic deletion at 1p36.31p36.23. RESULTS: Neuropsychological tests showed similar findings in two patients, with low information processing speed, slow memory consolidation, phonological disorders, working memory deficits, but mainly preserved executive function. Bilateral parietal and medial temporal abnormalities were found on brain MRI. Diffuse parieto-occipital and local left temporo-parietal decrease of FDG uptake was observed on PET images. CONCLUSION: These results suggest that CAMTA1 mutation may induce an unusual neuropsychological profile and parieto-temporal developmental abnormalities. We recommend screening for CAMTA1 mutations in patients with autosomal dominant mild intellectual disability presenting with similar a phenotype.

12p13.33 microdeletion including ELKS/ERC1, a new locus associated with childhood apraxia of speech.

Speech sound disorders are heterogeneous conditions, and sporadic and familial cases have been described. However, monogenic inheritance explains only a small proportion of such disorders, in particular in cases with childhood apraxia of speech (CAS). Deletions of <5 Mb involving the 12p13.33 locus is one of the least commonly deleted subtelomeric regions. Only four patients have been reported with such a deletion diagnosed with fluorescence in situ hybridisation telomere analysis or array CGH. To further delineate this rare microdeletional syndrome, a French collaboration together with a search in the Decipher database allowed us to gather nine new patients with a 12p13.33 subtelomeric or interstitial rearrangement identified by array CGH. Speech delay was found in all patients, which could be defined as CAS when patients had been evaluated by a speech therapist (5/9 patients). Intellectual deficiency was found in 5/9 patients only, and often associated with psychiatric manifestations of various severity. Two such deletions were inherited from an apparently healthy parent, but reevaluation revealed abnormal speech production at least in childhood, suggesting variable expressivity. The ELKS/ERC1 gene, which encodes for a synaptic factor, is found in the smallest region of overlap. These results reinforce the hypothesis that deletions of the 12p13.33 locus may be responsible for variable phenotypes including CAS associated with neurobehavioural troubles and that the presence of CAS justifies a genetic work-up.

De novo 15q21.1q21.2 deletion identified through FBN1 MLPA and refined by 244K array-CGH in a female teenager with incomplete Marfan syndrome.

Interstitial deletions involving the 15q21.1 band are very rare. Only 4 of these cases have been studied using molecular cytogenetic techniques in order to confirm the deletion of the whole FBN1 gene. The presence of clinical features of the Marfan syndrome (MFS) spectrum associated with mental retardation has been described in only 2/4 patients. Here we report on a 16-year-old female referred for suspicion of MFS (positive thumb and wrist sign, scoliosis, joint hyperlaxity, high-arched palate with dental crowding, dysmorphism, mitral insufficiency with dystrophic valve, striae). She had therefore 3 minor criteria according to the Ghent nosology. She also had speech disabilities but could follow normal school training. Direct sequencing of the FBN1, TGFBR1 and TGFBR2 genes was negative. MLPA revealed a genomic deletion of the whole FBN1 gene, confirmed by loss of heterozygosity of maternal alleles for several microsatellite markers surrounding the FBN1 gene. The deletion was confirmed by FISH using a FBN1 probe and was not found in the parents. Array-CGH permitted to define a 2.97 Mb deletion, which was the smallest 15q microdeletion including FBN1. Contrary to the other published observations, our proband does not exhibit mental retardation, but neuropsychological evaluations revealed an attention deficit as well as a deficit in information-processing speed. Haploinsufficiency of FBN1 is likely to contribute to the presence of MFS features. However, attenuated features could be explained because disturbances of TGF-beta signalling associated with FBN1 mutations do not exert full phenotypic effect through simple haploinsufficiency. Phenotypic variability in other patients with interstitial deletions including 15q21.1 band may reflect differences in deletion size and/or cys/trans modifying factors.

Brain injured patients versus multiple trauma patients: some neurobehavioral and psychopathological aspects.

BACKGROUND: The study aims to describe the neurobehavioral and psychopathological disorders in road crash victims with cerebral lesions compared with multiple trauma sufferers with no brain damage. METHODS: This study compares the neuropsychological and psychopathological developments of two groups of road crash victims (25 severe brain injuries (SBI) and 25 multiple traumas (MULT)) on the basis of the Neurobehavioral Scale, the SCL 90-R and the State/Trait Anxiety Scale. RESULTS: On the basis of the Neurobehavioral Scale, it was clear that the SBI patients suffered from significantly more disorders of type factor 1 (self-appraisal and flexible thinking), factor II (withdrawal), factor III (mood swings, irritability, disinhibition, excitement), factor IV (attention, slower motor responses, and mental fatigue), factor V (articulatory problems, problems of oral expression, and oral comprehension) and nonfactored disorders (exaggerated somatic concerns). On the SCL 90-R scale, we observed a higher level of obsessive symptoms in the SBI patients, whereas there was no significant difference between the two groups on the State/Trait Anxiety Scale. Unexpected results indicated that the multiple trauma patients suffered from memory troubles (60%), concept disorganization (32%), loss of initiative (36%), irritability (52%), unusual thought content (40%), mood swings (40%), attention difficulties (24%), suspiciousness (48%), and feelings of guilt (36%). CONCLUSION: Even though multiple trauma sufferers do not receive a psychologic assessment of their cerebral functioning, and do not benefit from any rehabilitation, they exhibit neurobehavioral and psychopathological disorders which need to be taken into account when designing rehabilitation programs. This study points toward new therapeutic methods for the treatment of multiple trauma sufferers.