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Histamine is involved in various physiological functions like sleep-wake cycle and stress regulation. The histamine N-methyltransferase (HNMT) enzyme is the only pathway for termination of histamine neurotransmission in the central nervous system. Experiments with HNMT knockout mice generated aggressive behaviours and dysregulation of sleep-wake cycles. Recently, seven members of two unrelated consanguineous families have been reported in whom two different missense HNMT mutations were identified. All showed severe intellectual disability, delayed speech development and mild regression from the age of 5 years without, however, any dysmorphisms or congenital abnormality. A diagnosis of mental retardation, autosomal recessive 51 was made. Here, we describe a severely mentally retarded adolescent male born from second cousins with a homozygous mutation in HNMT. His phenotypic profile comprised aggression, delayed speech, autism, sleep disturbances and gastro-intestinal problems. At early age, regression occurred. Treatment with hydroxyzine combined with a histamine-restricted diet resulted in significant general improvement.

The catenin beta-1 (CTNNB1) gene, encoding a sub-unit of the cadherin/catenin protein complex that is involved in the Wnt signalling pathway important for proper interneuron development, is considered to be causative for the rare autosomal dominant mental retardation syndrome, formerly called MRD19 but later renamed neurodevelopmental disorder with spastic diplegia and visual defects (NEDSDV). Its main characteristics are moderate to severe intellectual disability (ID), disruptive autistic behaviours, microcephaly, absent or limited speech, facial dysmorphisms, peripheral hypertonia/spasticity, motor delay and visual defects. So far, 35 patients have been reported with a de novo loss-of-function variant in CTNNB1. In two other patients, a deletion comprising the full gene was found. Four out of the 37 patients were of adult age (range: 27–51 years), while the majority was infant or adolescent (range: 0–20 years). Here, a 32-year-old severely intellectually disabled female patient is described in whom exome sequencing disclosed a de novo heterozygous splice site variant in the CTNNB1 gene [Chr3(GRCh37): g.41267064G>T; NM_001904.3: 23. c.734+1G>T; r. spl?]. Somatic investigation disclosed significant microcephaly and minor facial dysmorphisms. Neurological examination demonstrated severe kyphoscoliosis, distal spastic tetraparesis, especially of the legs with increased tendon reflexes and bilateral Babinski sign, resulting in severely impaired walking capability with a broad-based gait. Apart from strabismus, no ophthalmological abnormalities were found. Here, the reported variant in the CTNNB1 gene was not published earlier nor is included in the international databases. This specific variant is considered to be causative for the severe ID, autism and the somato-neurological phenotype of the patient and corresponds with a diagnosis of NEDSDV.

The catenin beta-1 (CTNNB1) gene, encoding a sub-unit of the cadherin/catenin protein complex that is involved in the Wnt signalling pathway important for proper interneuron development, is considered to be causative for the rare autosomal dominant mental retardation syndrome, formerly called MRD19 but later renamed neurodevelopmental disorder with spastic diplegia and visual defects (NEDSDV). Its main characteristics are moderate to severe intellectual disability (ID), disruptive autistic behaviours, microcephaly, absent or limited speech, facial dysmorphisms, peripheral hypertonia/spasticity, motor delay and visual defects. So far, 35 patients have been reported with a de novo loss-of-function variant in CTNNB1. In two other patients, a deletion comprising the full gene was found. Four out of the 37 patients were of adult age (range: 27–51 years), while the majority was infant or adolescent (range: 0–20 years). Here, a 32-year-old severely intellectually disabled female patient is described in whom exome sequencing disclosed a de novo heterozygous splice site variant in the CTNNB1 gene [Chr3(GRCh37): g.41267064G>T; NM_001904.3: 23. c.734+1G>T; r. spl?]. Somatic investigation disclosed significant microcephaly and minor facial dysmorphisms. Neurological examination demonstrated severe kyphoscoliosis, distal spastic tetraparesis, especially of the legs with increased tendon reflexes and bilateral Babinski sign, resulting in severely impaired walking capability with a broad-based gait. Apart from strabismus, no ophthalmological abnormalities were found. Here, the reported variant in the CTNNB1 gene was not published earlier nor is included in the international databases. This specific variant is considered to be causative for the severe ID, autism and the somato-neurological phenotype of the patient and corresponds with a diagnosis of NEDSDV.

Background: The minimal critical region in 2q23.1 deletion syndrome comprises one gene only, that is, the methyl-CpG-binding domain protein 5 (MBD5) gene. Since the phenotypes of patients with deletions, duplications or pathogenic variants of MBD5 show considerable overlap, the term MBD5-associated neurodevelopmental disorder (MAND) was proposed. These syndromes are characterized by intellectual disability, seizures of any kind and symptoms from the autism spectrum. In a very limited number of patients, MAND may be associated with regression starting either at early infancy or at midlife. Methods: The present paper describes a severely intellectually disabled autistic female with therapy resistant complex partial epilepsy starting at her 16the with gradual cognitive and behavioral regression towards her sixth decade. Results: Cognitive and behavioral regression occurred towards the patient's sixth decade. Exome sequencing disclosed a novel heterozygous pathogenic frameshift mutation of MBD5 that was considered to be causative for the combination of intellectual disability, treatment-resistant epilepsy and autism. Conclusion: The presented patient is the second with a pathogenic MBD5 mutation in whom the course of disease is suggestive of early onset dementia starting in her fifth decade. These findings stress the importance of exome sequencing, also in elderly intellectually disabled patients, particularly in those with autism.

Deletions of the 15q26 region encompassing the chromodomain helicase DNA binding domain 2 (CHD2) gene have been associated with intellectual disability, behavioral problems, and several types of epilepsy. Including the cases mentioned in ECARUCA (European cytogeneticists association register of unbalanced chromosome aberrations) and DECIPHER (database of genomic variation and phenotype in humans using ensembl resources), so far, a total of 13 intellectually disabled patients with a genetically proven deletion of the CHD2 gene are described, of whom eleven had a history of severe forms of epilepsy starting from a young age. In this article, a moderately intellectually disabled 15-year-old male with a 15q26.1–q26.2 interstitial deletion is reported, who was referred for analysis of two recent short-lasting psychotic episodes that were nonresponsive to antipsychotic treatment and recurrent disinhibited behaviors since early infancy. Careful interdisciplinary assessment revealed that the psychotic phenomena originated from a previously unrecognized absence epilepsy. Treatment with valproic acid was started which resulted in full remission of psychotic symptoms, and consequently, substantial improvement of behavior. It was concluded that in case of (rare) developmental disorders with genetically proven etiology, a detailed inventory of anamnestic data and description of symptomatology over time may elucidate epilepsy-related psychopathology for which a specific treatment regimen is needed.

The 16p11.2 microdeletion syndrome is characterized by a wide range of phenotypic expressions and is frequently associated with developmental delay, symptoms from the autism spectrum, epilepsy, congenital anomalies, and obesity. These phenotypes are often related to a proximal 16p11.2 deletion of approximately 600 kb (BP4-BP5) that includes the SH2B1 gene that is reported to be causative for morbid obesity. This more centromeric deletion is most strongly related to autism spectrum susceptibility and is functionally different from the more distal 16p12.2p11.2 region, which includes the so-called atypical 16p11.2 BP2-BP3 deletion (approximately 220 kb) presenting with developmental delay, behavioral problems and mild facial dysmorphisms. Here, an adult male with a long history of maladaptive behaviors is described who was referred for diagnostic assessment of his amotivational features. Extensive neuropsychological examination demonstrated rigid thinking, anxious beliefs, and ideas of reference in the presence of normal intelligence. Microarray analysis demonstrated a de novo 970 kb 16p11.2 BP1-BP4 microdeletion that can be regarded as explanatory for his behavioral profile. It is concluded that microdeletion syndromes are not exclusively related to intellectual disabilities and genetic testing is of putative relevance for the understanding of neuropsychiatric and neuropsychological phenomena.

Kallmann syndrome (KS) is a genetically heterogeneous and rare disorder characterised by the combination of hypothalamic hypogonadism and anosmia/hyposmia, a variable degree of intellectual disability and several somatic anomalies. In about one-third of the patients, mutations have been identified in at least seven different genes. Virtually no data are available about possible neuropsychiatric symptoms in KS. Here, a young adult male is described with a previous clinical diagnosis of KS and recent paranoid schizophrenia of which positive, but not negative symptoms, fully remitted upon treatment with antipsychotics. Neither genome-wide array analysis nor mutation analyses disclosed imbalances or mutations in any of presently known KS disease genes. This is the first report on a patient with KS and paranoid schizophrenia in whom extensive genetic analyses were performed. It is concluded that further studies are warranted in order to elucidate a possible increased risk for psychiatric symptoms in patients with KS.Copyright 2013 BMJ Publishing Group. All rights reserved.

With the introduction of new genetic techniques such as genome-wide array comparative genomic hybridization, studies on the putative genetic etiology of schizophrenia have focused on the detection of copy number variants (CNVs), ie, microdeletions and/or microduplications, that are estimated to be present in up to 3% of patients with schizophrenia. In this study, out of a sample of 100 patients with psychotic disorders, 80 were investigated by array for the presence of CNVs. The assessment of the severity of psychiatric symptoms was performed using standardized instruments and ICD-10 was applied for diagnostic classification. In three patients, a submicroscopic CNV was demonstrated, one with a loss in 1q21.1 and two with a gain in 1p13.3 and 7q11.2, respectively. The association between these or other CNVs and schizophrenia or schizophrenia-like psychoses and their clinical implications still remain equivocal. While the CNV affected genes may enhance the vulnerability for psychiatric disorders via effects on neuronal architecture, these insights have not resulted in major changes in clinical practice as yet. Therefore, genome-wide array analysis should presently be restricted to those patients in whom psychotic symptoms are paired with other signs, particularly dysmorphisms and intellectual impairment.

The 22q13.3 deletion, or Phelan-McDermid syndrome, is characterized by global intellectual disability, generalized hypotonia, severely delayed or absent speech associated with features of autism spectrum disorder, and minor dysmorphisms. Its behavioral phenotype comprises sleep disturbances, communication deficits, and motor perseverations. Data on psychological dysfunctions are so far not available. Previous studies have suggested that the loss of one copy of the gene SH3 and multiple ankyrin repeat domains 3 (SHANK3) is related to the neurobehavioral phenotype. Additional genes proximal to SHANK3 are also likely to play a role in the phenotype of patients with larger deletions. The present paper describes two adult brothers with an identical 2.15 Mb 22qter (22q13.32q13.33) deletion, of whom the youngest was referred for evaluation of recurrent mood changes. In both patients, magnetic resonance imaging of the brain showed hypoplasia of the vermis cerebelli. Extensive clinical examinations led to a final diagnosis of atypical bipolar disorder, of which symptoms fully remitted during treatment with a mood stabilizer. In the older brother, a similar psychopathological picture appeared to be present, although less severe and with a later onset. It is concluded that the behavioral phenotype of the 22q13.3 deletion syndrome comprises absent or delayed speech and perseverations with associated autistic-like features, whereas its psychopathological phenotype comprises an atypical bipolar disorder. The latter may have implications for the treatment regime of the syndrome-related behavioral disturbances.

Introduction: Manganese regulates many enzymes and is essential for normal development and body function. Chronic manganese intoxication has an insidious and progressive course and usually starts with complaints of headache, fatigue, sleep disturbances, irritability and emotional instability. Later, several organ systems may be affected and, due to neurotoxicity, an atypical parkinsonian syndrome may emerge. With regard to neuropsychiatry, an array of symptoms may develop up to 30 years after intoxication, of which gait and speech abnormalities, cognitive and motor slowing, mood changes and hallucinations are the most common. Psychotic phenomena are rarely reported. Case presentation: We describe the case of a 49-year-old Caucasian man working as a welder who was referred to our facility for evaluation of acute paranoid psychotic behavior. Our patient's medical history made no mention of any somatic complaints or psychiatric symptoms, and he had been involved in a professional career as a metalworker. On magnetic resonance imaging scanning of his brain, a bilateral hyperdensity of the globus pallidus, suggestive for manganese intoxication, was found. His manganese serum level was 52 to 97 nmol/L (range: 7 to 20 nmol/L). A diagnosis of organic psychotic disorder due to manganese overexposure was made. His psychotic symptoms disappeared within two weeks of treatment with low-dose risperidone. At three months later, serum manganese was decreased to slightly elevated levels and the magnetic resonance imaging T1 signal intensity was reduced. No signs of Parkinsonism were found and a definite diagnosis of manganese-induced apathy syndrome was made. Conclusion: Although neuropsychiatric and neurological symptoms caused by (chronic) manganese exposure have been reported frequently in the past, in the present day the disorder is rarely diagnosed. In this report we stress that manganese intoxication can still occur, in our case in a confined-space welder, and may present clin

Since the 1950s, several studies have been carried out to investigate the occurrence of schizophrenia-like psychoses in epilepsy. The psychopathological profile comprises symptoms from the affective, schizophrenic, and cognitive domains and the prevalence varies between 2% to 20%. Classification of such conditions is performed according to their temporal relationship with the seizure itself. Although it is well known that epilepsy may be associated with psychotic disorders, it is less widely recognized that relapsing psychotic phenomena may be the first and only symptom of epilepsy. In this research, two patients are described who were initially referred for recurrent episodes of bipolar affective disorder and schizophrenic psychosis, respectively. In both patients, a diagnosis of relapsing postictal psychotic states due to previously undiagnosed epilepsy was made and consequently, treatment with antiepileptics was started. During follow up over several months, they remained free of both epileptic and psychotic symptoms. Given the kaleidoscopic nature of the postictal psychosis and full recovery from this, such psychoses best meet the criteria for a cycloid psychosis. These observations illustrate diagnostic and therapeutic pitfalls due to the conceptual disintegration emerging from the inadequate separation between psychiatry and neurology. Therefore, the importance of a neuropsychiatric viewpoint should be promoted.

De diagnostiek van gedragsstoornissen en psychiatrische aandoeningen bij verstandelijk gehandicapten is buitengewoon complex vanwege het ontbreken van bruikbare diagnostische instrumenten en het geregeld vóórkomen van psychiatrische symptomen bij een specifieke genetische etiologie. In deze bijdrage wordt een diagnostische algoritme voorgesteld.

De diagnostiek van gedragsstoornissen en psychiatrische aandoeningen bij verstandelijk gehandicapten is buitengewoon complex vanwege het ontbreken van bruikbare diagnostische instrumenten en het geregeld vóórkomen van psychiatrische symptomen bij een specifieke genetische etiologie. In deze bijdrage wordt een diagnostische algoritme voorgesteld.

The current paper introduces concise neuropsychological assessment as an essential tool for studying the contribution of cognition and behavior in the expression of genetic syndromes, like Noonan syndrome (NS). Cognitive and behavioral findings in NS show intelligence scores across a wide range, with a mildly lowered average level. Language and motor development are often delayed, but no longer dysfunctional in adulthood. Continuing mild problems in selective and sustained attention are noted, as well as suboptimal organization skills and compromised abilities to structure complex information. These problems seem to culminate in learning difficulties, requiring attention for special needs in education. It seems that a complex of psychosocial immaturity, alexithymia and amenable traits is typical of NS patients. Consequently, psychopathology or psychological problems in leading a self-serving life may often remain underreported. This is why the authors advocate the integration of the domain of social cognition and personality in NS assessment.

Background and Objectives: Testosterone deficiency has been implicated in the etiology of depression although there is an ongoing debate on the nature of this association. There is a paucity of data about the psychological impact of hypogonadism in genetic disorders associated with testosterone deficiency. Methods:A 57-year-old male is described who was referred for treatment resistant depression. His history showed infertility and lowered testosterone. A selective literature review is given to clarify the patient's clinical condition. Results: Cytogenetic analysis demonstrated a Robertsonian translocation between chromosomes 13 and 14 that accounted for his infertility. The psychopathological picture did not meet the criteria for a major depressive disorder but was characterized by symptoms of apathy or avolition. These symptoms were most probably aggravated by previous long lasting treatment with antidepressants. Conclusions: Testosterone deficiency may be related to motivational deficits that should not be misunderstood for depressive illness. Apathy is probably an underestimated side effect of antidepressants.