[Genetics of ADHD in clinical practice]. / Genética del TDAH en la práctica clínica.

Attention-deficit/hyperactivity disorder (ADHD) is a complex and heterogeneous neurodevelopmental disorder from a causal, clinical and prognostic perspective. Research reflects its multifactorial nature with a prominent role of genetic factors. Population studies have historically pointed to the involvement of numerous genetic variants of small effect size, which hardly by themselves increase the risk of presenting the disorder and hardly justify its high heritability. Many of them are present in more than 60% of the general population, suggesting their modulatory rather than causal role. However, after the irruption of new genetic techniques in the last 15 years, a greater number of cases are being identified with genetic disorders (many of them monogenic), whose genetic variants alone explain the presence of ADHD. A detailed study of the personal and family history, as well as a complete physical examination, can help to identify some of them. The identification of the cause in this group of cases has a crucial value in clinical counseling, genetic-familial counseling and prognostic anticipation, as well as in the performance or avoidance of complementary studies and in the design of the intervention plan.

El trastorno por déficit de atención/hiperactividad (TDAH) es un trastorno del neurodesarrollo complejo y heterogéneo desde una perspectiva causal, clínica y pronóstica. La investigación refleja su carácter multifactorial con un papel destacado de los factores genéticos. Los estudios poblacionales han señalado históricamente la implicación de numerosas variantes genéticas de escaso tamaño de efecto, las cuales por sí mismas apenas incrementan el riesgo de TDAH y difícilmente justifican su elevada heredabilidad. Muchas de ellas están presentes en más del 60% de la población general, lo que sugiere su papel modulador más que causal. No obstante, gracias a la irrupción de nuevas técnicas genéticas en los últimos 15 años, se están identificando un mayor número de casos con trastornos genéticos (muchos de ellos monogénicos), cuyas variantes genéticas explican por sí mismas la presencia del TDAH. El estudio detallado de los antecedentes personales y familiares, así como una exploración física completa, puede ayudar a identificar algunos de ellos. La identificación de la causa en este conjunto de casos tiene un valor crucial en el asesoramiento clínico, el consejo genético-familiar y la anticipación pronóstica, así como en la realización o evitación de estudios complementarios y en el diseño del plan terapéutico.

El impacto del TDAH sobre la lectura / The impact of ADHD on reading

Resumen Más allá de la frecuente coexistencia del trastorno por déficit de atención con hiperactividad (TDAH) y el trastorno específico del aprendizaje de la lectura, la presente revisión pretende examinar la evidencia empírica disponible sobre cómo el TDAH impacta negativamente sobre el aprendizaje de la lectura. Los datos existentes apuntan a que la presencia del trastorno (especialmente los síntomas de falta de atención), puede afectar a i) la correcta adquisición de lectura, ya sea de manera directa o a través de su influencia sobre los precursores de la lectura; ii) las propias habilidades de decodificación (precisión y fluidez lectora), tanto de manera directa como indirecta a través de su influencia sobre procesos cognitivos como la distracción o las funciones ejecutivas; y ii) la comprensión lectora, probablemente de manera indirecta por las dificultades eje cutivas y en la memoria de trabajo verbal características del TDAH. Estas conclusiones presentan importantes implicaciones para caracterizar e intervenir mejor sobre las dificultades lectoras en el TDAH, ya sean clínicas o subclínicas.

Abstract Beyond the frequent coexistence of attention deficit hyperactivity disorder (ADHD) and reading dis order (dyslexia), the present review aims to examine the available empirical evidence on how ADHD negatively impacts on learning to read. Existing data suggest that the presence of the disorder (especially inattention symp toms), may affect i) the correct acquisition of reading, either directly or through its influence on the precursors to reading; ii) decoding skills themselves (reading accuracy and fluency), both directly and indirectly through its influence on cognitive processes such as distractibility or executive functions; and iii) reading comprehension, probably indirectly through the executive and verbal memory difficulties characteristic of ADHD. These findings have important implications for better characterizing and intervening on reading difficulties in ADHD, whether clinical or subclinical.

[The impact of ADHD on reading]. / El impacto del TDAH sobre la lectura.

Beyond the frequent coexistence of attention deficit hyperactivity disorder (ADHD) and reading disorder (dyslexia), the present review aims to examine the available empirical evidence on how ADHD negatively impacts on learning to read. Existing data suggest that the presence of the disorder (especially inattention symptoms), may affect i) the correct acquisition of reading, either directly or through its influence on the precursors to reading; ii) decoding skills themselves (reading accuracy and fluency), both directly and indirectly through its influence on cognitive processes such as distractibility or executive functions; and iii) reading comprehension, probably indirectly through the executive and verbal memory difficulties characteristic of ADHD. These findings have important implications for better characterizing and intervening on reading difficulties in ADHD, whether clinical or subclinical.

Más allá de la frecuente coexistencia del trastorno por déficit de atención con hiperactividad (TDAH) y el trastorno específico del aprendizaje de la lectura, la presente revisión pretende examinar la evidencia empírica disponible sobre cómo el TDAH impacta negativamente sobre el aprendizaje de la lectura. Los datos existentes apuntan a que la presencia del trastorno (especialmente los síntomas de falta de atención), puede afectar a i) la correcta adquisición de lectura, ya sea de manera directa o a través de su influencia sobre los precursores de la lectura; ii) las propias habilidades de decodificación (precisión y fluidez lectora), tanto de manera directa como indirecta a través de su influencia sobre procesos cognitivos como la distracción o las funciones ejecutivas; y ii) la comprensión lectora, probablemente de manera indirecta por las dificultades ejecutivas y en la memoria de trabajo verbal características del TDAH. Estas conclusiones presentan importantes implicaciones para caracterizar e intervenir mejor sobre las dificultades lectoras en el TDAH, ya sean clínicas o subclínicas.

Mutations in the COL18A1 gen associated with knobloch syndrome and structural brain anomalies: a novel case report and literature review of neuroimaging findings.

. COL18A1 gene mutations have been associated with Knobloch syndrome, which is characterized by ocular and brain abnormalities. Here we report a 4.5 years-old male child with autism and two novel COL18A1 mutations (NM_030582.4: c.1883_1891dup and c.1787C>T). Hypermetropic astigmatism, but not brain migration disorders, was observed. However, an asymmetric pattern of cerebellar perfusion and a smaller arcuate fascicle were found.  Low levels of collagen XVIII were also observed in the patient´s serum. Thus, biallelic loss-of-function mutations in COL18A1 may be a new cause of autism  without the brain malformations typically reported in patients with Knobloch syndrome.

Biallelic ELMO3 mutations and loss of function for DOCK-mediated RAC1 activation result in intellectual disability.

The engulfment and cell motility 3 (ELMO3) protein belongs to the ELMO-family of proteins. ELMO proteins form a tight complex with the DOCK1-5 guanine nucleotide exchange factors that regulate RAC1 spatiotemporal activation and signalling. DOCK proteins and RAC1 are known to have fundamental roles in central nervous system development. Here, we searched for homozygous or compound heterozygous mutations in the ELMO3 gene in 390 whole exomes sequenced in trio in individuals with neurodevelopmental disorders compatible with a genetic origin. We found a compound heterozygous mutation in ELMO3 (c.1153A>T, p.Ser385Cys and c.1009 G > A, p.Val337Ile) in a 5 year old male child with autism spectrum disorder (ASD) and developmental delay. These mutations did not interfere with the formation of an ELMO3/DOCK1 complex, but markedly impaired the ability of the complex to promote RAC1-GTP-loading. Consequently, cells expressing DOCK1 and either of the ELMO3 mutants displayed impaired migration and invasion. Collectively, our results suggest that biallelic loss-of-function mutations in ELMO3 may cause a developmental delay and provide new insight into the role of ELMO3 in neurodevelopmental as well as the pathological consequences of ELMO3 mutations.

A mild clinical and neuropsychological phenotype of Renpenning syndrome: A new case report with a maternally inherited PQBP1 missense mutation.

Mutations in the PQBP1 gene are associated with Renpenning syndrome (RENS1, MIM# 309500). Most cases are characterized by intellectual disability, but a detailed neuropsychological profile has not yet been established. The present case study of a 8.5 years-old male child with a missense novel mutation in the PQBP1 gene expands existing understanding of this syndrome by presenting a milder clinical and neuropsychological phenotype. Whole exome trio analysis sequencing revealed a maternally inherited PQBP1 missense mutation in chromosome X [NM_001032383.1, c.727C > T (p.Arg243Trp)]. Variant functional studies demonstrated a significant reduction in the interaction between PQBP1 and the component of the nuclear pre-mRNA splicing machinery, U5-15KD. A comprehensive neuropsychological assessment revealed marked deficits in processing speed, attention and executive functioning (including planning, inhibitory control and working memory) without intellectual disability. Several components of language processing were also impaired. These results support that this mutation partially disrupts the function of this gene, which is known to play critical roles in embryonic and neural development. As most of the genomic PQBP1 abnormalities associated with intellectual disability have been found to be loss-of-function mutations, we hypothesize that a partial loss-of-function of this variant is associated with a mild behavioral and neuropsychological phenotype.

Biallelic SYNE2 Missense Mutations Leading to Nesprin-2 Giant Hypo-Expression Are Associated with Intellectual Disability and Autism.

Autism spectrum disorder (ASD) is a group of neurological and developmental disabilities characterised by clinical and genetic heterogeneity. The current study aimed to expand ASD genotyping by investigating potential associations with SYNE2 mutations. Specifically, the disease-causing variants of SYNE2 in 410 trios manifesting neurodevelopmental disorders using whole-exome sequencing were explored. The consequences of the identified variants were studied at the transcript level using quantitative polymerase chain reaction (qPCR). For validation, immunofluorescence and immunoblotting were performed to analyse mutational effects at the protein level. The compound heterozygous variants of SYNE2 (NM_182914.3:c.2483T>G; p.(Val828Gly) and NM_182914.3:c.2362G>A; p.(Glu788Lys)) were identified in a 4.5-year-old male, clinically diagnosed with autism spectrum disorder, developmental delay and intellectual disability. Both variants reside within the nesprin-2 giant spectrin repeat (SR5) domain and are predicted to be highly damaging using in silico tools. Specifically, a significant reduction of nesprin-2 giant protein levels is revealed in patient cells. SYNE2 transcription and the nuclear envelope localisation of the mutant proteins was however unaffected as compared to parental control cells. Collectively, these data provide novel insights into the cardinal role of the nesprin-2 giant in neurodevelopment and suggest that the biallelic hypomorphic SYNE2 mutations may be a new cause of intellectual disability and ASD.

Abnormal frontal gyrification pattern and uncinate development in patients with KBG syndrome caused by ANKRD11 aberrations.

KBG syndrome is characterized by dental, craniofacial and skeletal anomalies, short stature and global developmental delay or intellectual disability. It is caused by microdeletions or truncating mutations of ANKRD11. We report four unrelated probands with this syndrome due to de novo ANKRD11 aberrations that may contribute to a better understanding of the genetics and pathophysiology of this autosomal dominant syndrome. Clinical, cognitive and MRI assessments were performed. Three of the patients showed normal intellectual functioning, whereas the fourth had a borderline level of intellectual functioning. However, all of them showed deficits in various cognitive and socioemotional processes such as attention, executive functions, empathy or pragmatic language. Moreover, all probands displayed marked asymmetry of the uncinate fascicles and an abnormal gyrification pattern in the left frontal lobe. Thus, structural neuroimaging anomalies seem to have been overlooked in this syndrome. Disturbed frontal gyrification and/or lower structural integrity of the uncinate fascisulus might be unrecognized neuroimaging features of KBG syndrome caused by ANKRD11 aberrations. Present results also point out that this syndrome is not necessarily associated with global developmental delay and intellectual disability, but it can be related to other neurodevelopmental disorders or subclinical levels of attention-deficit hyperactivity disorder, autism, communication disorders or specific learning disabilities.

ANO3 and early-onset dyskinetic encephalopathy.

Mutations in the ANO3 gene have been associated with autosomal dominant craniocervical dystonia. However, little else is known about the genotype-phenotype characteristics of this disorder. Here we describe a 3 years-old girl with distal myoclonic dystonia. Whole exome sequencing in trio revealed a de novo missense ANO3 variant not previously described in international databases. A global psychomotor regression was observed once dystonia was present. Brain MRI changes paralleled these findings: whereas MRI at the age of 18 months was normal, mild brain and cerebellar atrophy was observed 18 months later. These results suggest that missense mutations in ANO3 may underlie complex disorders particularly characterized by early psychomotor regression and dystonia.

Cingulate Cortical Thickness and Dopamine Transporter ( DAT1) Genotype in Children and Adolescents With ADHD.

OBJECTIVE: This study aimed to examine the influence of dopamine transporter gene ( DAT1) 3'UTR genotype on cingulate cortical thickness in a large sample of children and adolescents with ADHD. METHOD: Brain MRIs were acquired from 46 ADHD patients with homozygosity for the 10-repeat allele and 52 ADHD patients with a single copy or no copy of the allele. The cingulate cortex of each MRI scan was automatically parceled into sulci and gyri as well as into Brodmann areas (BA). RESULTS: There were no group differences in age, gender, full-scale intelligence quotient, symptom severity, treatment status, comorbidity, or mean overall cortical thickness. Sulcus/gyrus- and BA-based analyses revealed that patients homozygous for the 10-repeat allele showed significantly greater thickness in right cingulate gyrus and right BA 24 compared with 9-repeat carriers. CONCLUSION: These findings suggest that thickness of cingulate cortex is influenced by the presence of the 10-repeat allele in ADHD.

Migraña hemipléjica y secuencia pseudocontinuous arterial spin-labeling / Hemiplegic migraine and arterial spin labelling sequence

No disponible

Mutations in BRAT1 cause autosomal recessive progressive encephalopathy: Report of a Spanish patient.

We describe a 4-year-old male child born to non-consanguineous Spanish parents with progressive encephalopathy (PE), microcephaly, and hypertonia. Whole exome sequencing revealed compound heterozygous BRAT1 mutations [c.1564G > A (p.Glu522Lys) and c.638dup (p.Val214Glyfs*189)]. Homozygous and compound heterozygous BRAT1 mutations have been described in patients with lethal neonatal rigidity and multifocal seizure syndrome (MIM# 614498). The seven previously described patients suffered from uncontrolled seizures, and all of those patients died in their first months of life. BRAT1 acts as a regulator of cellular proliferation and migration and is required for mitochondrial function. The loss of these functions may explain the cerebral atrophy observed in this case of PE. This case highlights the extraordinary potential of next generation technologies for the diagnosis of rare genetic diseases, including PE. Making a prompt diagnosis of PE is important for genetic counseling and disease management.

Cortical thickness differences in the prefrontal cortex in children and adolescents with ADHD in relation to dopamine transporter (DAT1) genotype.

Several lines of evidence suggest that the dopamine transporter gene (DAT1) plays a crucial role in attention deficit hyperactivity disorder (ADHD). Concretely, recent data indicate that the 10-repeat (10R) DAT1 allele may mediate neuropsychological functioning, response to methylphenidate, and even brain function and structure in children with ADHD. This study aimed to investigate the influence of 10R DAT1 on thickness of the prefrontal cortex in children and adolescents with ADHD. To this end, brain magnetic resonance images were acquired from 33 patients with homozygosity for the 10R allele and 30 patients with a single copy or no copy of the allele. The prefrontal cortex of each MRI scan was automatically parceled into regions of interest (ROIs) based on Brodmann areas (BA). The two groups were matched for age, gender, IQ, ADHD subtype, symptom severity, comorbidity and medication status. However, patients with two copies of the 10R allele exhibited significantly decreased cortical thickness in right BA 46 relative to patients with one or fewer copies of the allele. No other prefrontal ROI differed significantly between the two groups. Present findings suggest that cortical thickness of right lateral prefrontal cortex (BA 46) is influenced by the presence of the DAT1 10 repeat allele in children and adolescents with ADHD.

[Attention deficit hyperactivity disorder and adoption]. / Trastorno por déficit de atención/hiperactividad y adopción.

INTRODUCTION: The term adoption or adoptive filiation is understood as referring to the legal act by which family ties are created between two persons such that a relationship of fatherhood or motherhood is established between them. AIMS. The purpose of this study is to outline the problems derived from prenatal exposure to alcohol and other risk factors, from hypostimulation during the 'critical period' in institutionalised patients (especially those adopted from eastern European countries) and their relation with attention deficit hyperactivity disorder (ADHD). This work also seeks to take a deeper look into the diagnosis, prevention and treatment of these problems. DEVELOPMENT: These children have problems in terms of psychosocial relationships, behavioural problems, delayed language or reading development and, above all, ADHD. In practice it is extremely difficult to separate the two factors during the assessment of children adopted from eastern European countries in neuropaediatric consultations. Exactly how all these factors are interrelated is not well understood. CONCLUSIONS: There is a close relationship between prenatal exposure to alcohol and the consequences of adoption. There is a need for placebo-controlled randomised studies, with larger population samples, that test the benefits and profile of side effects, both with psychostimulants and with atomoxetine in this group of patients.

TITLE: Trastorno por deficit de atencion/hiperactividad y adopcion.Introduccion. Se entiende por adopcion o filiacion adoptiva el acto juridico mediante el cual se crea un vinculo de parentesco entre dos personas, de tal forma que se establece entre ellas una relacion de paternidad o maternidad. Objetivos. Tratar de exponer los problemas derivados de la exposicion prenatal al alcohol y otros factores de riesgo, de la hipoestimulacion durante el 'periodo critico' en pacientes institucionalizados (especialmente aquellos adoptados de paises del este de Europa) y su relacion con el trastorno de deficit de atencion/hiperactividad (TDAH). Realizar una aproximacion al diagnostico, prevencion y tratamiento de estos problemas. Desarrollo. Estos niños presentan problemas de relacion psicosocial, problemas conductuales, retraso del desarrollo del lenguaje o de la lectura y, sobre todo, TDAH. Existe una enorme dificultad practica a la hora de separar ambos factores durante la evaluacion de niños adoptados de paises del este de Europa en las consultas de neuropediatria. La interrelacion de todos estos factores no es bien conocida. Conclusiones. Existe una intima relacion entre la exposicion prenatal al alcohol y las consecuencias de la adopcion. Se necesitan estudios aleatorizados controlados con placebo, con mayores muestras poblacionales, que comprueben el beneficio y perfil de efectos secundarios, tanto con psicoestimulantes como con la atomoxetina en este grupo de pacientes.

Cortical thinning of temporal pole and orbitofrontal cortex in medication-naïve children and adolescents with ADHD.

Structural and functional brain studies on attention deficit/hyperactivity disorder (ADHD) have primarily examined anatomical abnormalities in the prefronto-striatal circuitry (especially, dorsal and lateral areas of the prefrontal cortex and dorsal striatum). There is, however, increased evidence that several temporal lobe regions could play an important role in ADHD. The present study used MRI-based measurements of cortical thickness to examine possible differences in both prefrontal and temporal lobe regions between medication-näive patients with ADHD (N = 50) and age- and sex-matched typically developing controls (N = 50). Subjects with ADHD exhibited significantly decreased cortical thickness in the right temporal pole and orbitofrontal cortex (OFC) relative to healthy comparison subjects. These differences remained significant after controlling for confounding effects of age, overall mean cortical thickness and comorbid externalizing conditions, such as oppositional defiant and conduct disorders. These results point to the involvement of the temporal pole and OFC in the neuropathology of ADHD. Moreover, present findings add evidence to the assumption that multiple brain regions and psychological processes are associated with ADHD.

Craniosynostosis, psychomotor retardation, and facial dysmorphic features in a Spanish patient with a 4q27q28.3 deletion.

CASE REPORT: We describe an unusual clinical case with an 11-Mb deletion at 4q27 (chr4: 123094652-134164491), craniosynostosis (CS), mild psychomotor retardation, and facial dysmorphic features. This deletion involves 18 genes; FGF2, NUDT6, and SPRY1 are primarily or secondarily implicated in human cranial bone and sagittal suture development and could play an important role in CS. CONCLUSIONS: Clinicians should always contemplate genetic studies in patients with syndromic CS. Mutational targeted genetic testing is appropriate for patients with classical or specific CS syndrome. Nevertheless, array comparative genomic hybridization (array CGH) should be considered as a first-line test in nontypical syndromic CS phenotype. Cytogenetic studies are decisive for genetic counseling indeed.

Microduplication 10q24.31 in a Spanish girl with scoliosis and myopathy: the critical role of LBX.

LBX1 plays a cardinal role in neuronal and muscular development in animal models. Its function in humans is unknown; it has been reported as a candidate gene for idiopathic scoliosis. Our goal is to document the first clinical case of a microduplication at 10q24.31 (chr10:102927883-103053612, hg19), affecting exclusively LBX1. The patient, a 12-year-old girl, showed attention problems, dyspraxia, idiopathic congenital scoliosis, and marked hypotrophy of paravertebral muscles. Her paternal aunt had a severe and progressive myopathy with a genetic study that revealed the same duplication. We propose to consider genetic studies, particularly of LBX1, in patients with scoliosis and/or hypotrophy-hypoplasia of paravertebral muscles of unknown etiology.

Cerebral palsy, epilepsy, and severe intellectual disability in a patient with 3q29 microduplication syndrome.

Interstitial microduplication of 3q29 has been recently described. Individuals with this syndrome have widely variable phenotypes. We describe the first clinical case with a 1.607 Mb duplication at 3q29 (chr3: 195,731,956-197,339,329), accompanied by severe intellectual disability, epilepsy, and cerebral palsy. This duplication involves 22 genes; PAK2, DLG1, BDH1, and FBXO45 are implicated in neuronal development and synaptic function and could play an important role in this syndrome. We propose considering genetic studies, particularly array comparative genomic hybridization, in patients with epilepsy and/or cerebral palsy of unknown etiology when dysmorphic features are present.

Cortical thickness at the time of the initial attack in two patients with paediatric relapsing-remitting multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system with a low incidence in the paediatric population; cortical atrophy is often striking, even in the early stages of the disease. Evidence of cortical thinning in childhood MS is scant. AIMS: This study aimed to assess cortical thickness in paediatric patients during the initial attack of remitting-relapsing MS. METHODS: We report two cases of remitting-relapsing MS, with initial attacks at 12 and 16 years of age. We analysed brain cortical thickness (CTh) in these patients and compared these data to the CTh of a control group comprised of six 12-year-old females and six 16-year-old males. RESULTS: Both cases exhibited a total brain CTh significantly below that of the control group. This difference was also observed when analysing the CTh of all lobes except the left parietal lobe in one of the cases. CONCLUSIONS: Cortical atrophy is already present at the time of onset of MS. Studies with larger patient populations that have a more homogenous clinical presentation could identify the time of onset of cortical atrophy and use this parameter as a prognostic and/or treatment marker of MS.

In utero diagnosis of PHACE syndrome by fetal magnetic resonance imaging (MRI).

The acronym PHACE describes the association of facial hemangioma with anomalies of the posterior fossa, cerebral arteries, and cardiovascular and ocular alterations. This study presents a case of diagnostic suspicion based on fetal MRI. We report the case of a pregnant woman whose 26-week MRI revealed a female fetus with hypoplasia of the right cerebellar hemisphere and right microphthalmia, leading to the suspicion of PHACE syndrome. The diagnosis was confirmed at birth, together with other criteria: facial hemangioma, absent posterior inferior cerebellar artery, and dysplasia of the right internal carotid artery. To our knowledge, this is the first live case described prenatally with both ocular and cerebellar findings on fetal MRI that suggest PHACE syndrome. The prenatal presence of 2 PHACE criteria led to the suspicion of this syndrome, and prenatal diagnostic criteria might be developed to improve information regarding the prognosis of cerebellar malformations.