Impact of theta transcranial alternating current stimulation on language production in adult classic galactosemia patients.

Patients with classic galactosemia (CG), an inborn error of galactose metabolism, suffer from impairments in cognition, including language processing. Potential causes are atypical brain oscillations. Recent electroencephalogram (EEG) showed differences in the P300 event-related-potential (ERP) and alterations in the alpha/theta-range during speech planning. This study investigated whether transcranial alternating current stimulation (tACS) at theta-frequency compared to sham can cause a normalization of the ERP post stimulation and improves language performance. Eleven CG patients and fourteen healthy controls participated in two tACS-sessions (theta 6.5 Hz/sham). They were engaged in an active language task, describing animated scenes at three moments, that is, pre/during/post stimulation. Pre and post stimulation, behavior (naming accuracy, voice-onset-times; VOT) and mean-amplitudes of ERP were compared, by means of a P300 time-window analysis and cluster-based-permutation testing during speech planning. The results showed that theta stimulation, not sham, significantly reduced naming error-percentage in patients, not in controls. Theta did not systematically speed up naming beyond a general learning effect, which was larger for the patients. The EEG analysis revealed a significant pre-post stimulation effect (P300/late positivity), in patients and during theta stimulation only. In conclusion, theta-tACS improved accuracy in language performance in CG patients compared to controls and altered the P300 and late positive ERP-amplitude, suggesting a lasting effect on neural oscillation and behavior.

Brain function in classic galactosemia, a galactosemia network (GalNet) members review.

Classic galactosemia (CG, OMIM #230400, ORPHA: 79,239) is a hereditary disorder of galactose metabolism that, despite treatment with galactose restriction, affects brain function in 85% of the patients. Problems with cognitive function, neuropsychological/social emotional difficulties, neurological symptoms, and abnormalities in neuroimaging and electrophysiological assessments are frequently reported in this group of patients, with an enormous individual variability. In this review, we describe the role of impaired galactose metabolism on brain dysfunction based on state of the art knowledge. Several proposed disease mechanisms are discussed, as well as the time of damage and potential treatment options. Furthermore, we combine data from longitudinal, cross-sectional and retrospective studies with the observations of specialist teams treating this disease to depict the brain disease course over time. Based on current data and insights, the majority of patients do not exhibit cognitive decline. A subset of patients, often with early onset cerebral and cerebellar volume loss, can nevertheless experience neurological worsening. While a large number of patients with CG suffer from anxiety and depression, the increased complaints about memory loss, anxiety and depression at an older age are likely multifactorial in origin.

A Delphi Survey Study to Formulate Statements on the Treatability of Inherited Metabolic Disorders to Decide on Eligibility for Newborn Screening.

The Wilson and Jungner (W&J) and Andermann criteria are meant to help select diseases eligible for population-based screening. With the introduction of next-generation sequencing (NGS) methods for newborn screening (NBS), more inherited metabolic diseases (IMDs) can technically be included, and a revision of the criteria was attempted. This study aimed to formulate statements and investigate whether those statements could elaborate on the criterion of treatability for IMDs to decide on eligibility for NBS. An online Delphi study was started among a panel of Dutch IMD experts (EPs). EPs evaluated, amended, and approved statements on treatability that were subsequently applied to 10 IMDs. After two rounds of Delphi, consensus was reached on 10 statements. Application of these statements selected 5 out of 10 IMDs proposed for this study as eligible for NBS, including 3 IMDs in the current Dutch NBS. The statement: 'The expected benefit/burden ratio of early treatment is positive and results in a significant health outcome' contributed most to decision-making. Our Delphi study resulted in 10 statements that can help to decide on eligibility for inclusion in NBS based on treatability, also showing that other criteria could be handled in a comparable way. Validation of the statements is required before these can be applied as guidance to authorities.

Development of tools to facilitate the diagnosis of hereditary fructose intolerance.

Although hereditary fructose intolerance (HFI) is an inborn error of fructose metabolism that classically presents at infancy, the diagnosis is often missed or delayed. In this study, we aimed to develop tools to facilitate the diagnosis of HFI. The intake of fructose-containing food products, that is, fruit, fruit juice and sugar-sweetened beverages, was assessed by a 3-day food diary in adult HFI patients (n = 15) and age, sex, and BMI-matched controls (n = 15). Furthermore, glycosylation of transferrin was examined using high-resolution mass spectrometry and abnormally glycosylated transferrin was expressed as ratio of normal glycosylated transferrin. We found that the sensitivity and specificity of the 3-day food diary for the intake of at least one fructose-containing food product were both 100%. Both mono-glyco:diglyco transferrin and a-glyco+mono-glyco:di-glyco transferrin were greater in HFI patients and had a high-discriminatory power (area under the receiver operating characteristic curve: 0.97 and 0.94, respectively). In this well-characterized cohort of adult HFI patients, the 3-day food questionnaire and the glycosylation pattern of transferrin are valuable tools to facilitate the recognition and diagnosis of HFI in adult patients.

Germline AGO2 mutations impair RNA interference and human neurological development.

ARGONAUTE-2 and associated miRNAs form the RNA-induced silencing complex (RISC), which targets mRNAs for translational silencing and degradation as part of the RNA interference pathway. Despite the essential nature of this process for cellular function, there is little information on the role of RISC components in human development and organ function. We identify 13 heterozygous mutations in AGO2 in 21 patients affected by disturbances in neurological development. Each of the identified single amino acid mutations result in impaired shRNA-mediated silencing. We observe either impaired RISC formation or increased binding of AGO2 to mRNA targets as mutation specific functional consequences. The latter is supported by decreased phosphorylation of a C-terminal serine cluster involved in mRNA target release, increased formation of dendritic P-bodies in neurons and global transcriptome alterations in patient-derived primary fibroblasts. Our data emphasize the importance of gene expression regulation through the dynamic AGO2-RNA association for human neuronal development.

Pathogenic variants in TNRC6B cause a genetic disorder characterised by developmental delay/intellectual disability and a spectrum of neurobehavioural phenotypes including autism and ADHD.

BACKGROUND: Rare variants in hundreds of genes have been implicated in developmental delay (DD), intellectual disability (ID) and neurobehavioural phenotypes. TNRC6B encodes a protein important for RNA silencing. Heterozygous truncating variants have been reported in three patients from large cohorts with autism, but no full phenotypic characterisation was described. METHODS: Clinical and molecular characterisation was performed on 17 patients with TNRC6B variants. Clinical data were obtained by retrospective chart review, parent interviews, direct patient interaction with providers and formal neuropsychological evaluation. RESULTS: Clinical findings included DD/ID (17/17) (speech delay in 94% (16/17), fine motor delay in 82% (14/17) and gross motor delay in 71% (12/17) of subjects), autism or autistic traits (13/17), attention deficit and hyperactivity disorder (ADHD) (11/17), other behavioural problems (7/17) and musculoskeletal findings (12/17). Other congenital malformations or clinical findings were occasionally documented. The majority of patients exhibited some dysmorphic features but no recognisable gestalt was identified. 17 heterozygous TNRC6B variants were identified in 12 male and five female unrelated subjects by exome sequencing (14), a targeted panel (2) and a chromosomal microarray (1). The variants were nonsense (7), frameshift (5), splice site (2), intragenic deletions (2) and missense (1). CONCLUSIONS: Variants in TNRC6B cause a novel genetic disorder characterised by recurrent neurocognitive and behavioural phenotypes featuring DD/ID, autism, ADHD and other behavioural abnormalities. Our data highly suggest that haploinsufficiency is the most likely pathogenic mechanism. TNRC6B should be added to the growing list of genes of the RNA-induced silencing complex associated with ID/DD, autism and ADHD.

[Neonatal hypotonia]. / Hypotonie bij neonaten.

Hypotonia in neonates is a relatively common symptom, and has a broad differential diagnosis. Despite advances in diagnostic techniques over the past few years, understanding where hypotonia in a neonate originates remains a challenge. Hypotonia can be a result of diseases of the central or peripheral nervous system; differentiation between a central or a peripheral origin is helpful as a first step in the diagnostic evaluation. This article describes a systematic approach to clinical evaluation of a neonate with hypotonia, resulting in an adequate selection of specific diagnostic tests to establish the diagnosis.

De Novo Variants in MAPK8IP3 Cause Intellectual Disability with Variable Brain Anomalies.

Using exome sequencing, we have identified de novo variants in MAPK8IP3 in 13 unrelated individuals presenting with an overlapping phenotype of mild to severe intellectual disability. The de novo variants comprise six missense variants, three of which are recurrent, and three truncating variants. Brain anomalies such as perisylvian polymicrogyria, cerebral or cerebellar atrophy, and hypoplasia of the corpus callosum were consistent among individuals harboring recurrent de novo missense variants. MAPK8IP3 has been shown to be involved in the retrograde axonal-transport machinery, but many of its specific functions are yet to be elucidated. Using the CRISPR-Cas9 system to target six conserved amino acid positions in Caenorhabditis elegans, we found that two of the six investigated human alterations led to a significantly elevated density of axonal lysosomes, and five variants were associated with adverse locomotion. Reverse-engineering normalized the observed adverse effects back to wild-type levels. Combining genetic, phenotypic, and functional findings, as well as the significant enrichment of de novo variants in MAPK8IP3 within our total cohort of 27,232 individuals who underwent exome sequencing, we implicate de novo variants in MAPK8IP3 as a cause of a neurodevelopmental disorder with intellectual disability and variable brain anomalies.

Early warning signs in misrecognized secondary pediatric psychotic disorders: a systematic review.

Childhood psychotic symptoms are not uncommon, but lack an evidence-based diagnostic approach. Hallucinations, delusions and other psychotic symptoms, without endangered vital symptoms, can be the result of a primary psychiatric disorder or can be the presenting symptom of an underlying somatic disease. It is important to discriminate between these origins because their diagnostic and therapeutic approaches differ substantially. We searched the existing literature to present a first overview of warning symptoms of underlying somatic disease in children with psychotic symptoms. We obtained data through a study of major textbooks and guidelines, and through a systematic review in PubMed, Embase and PsycINFO databases. We included case reports, cohort studies, and reviews. Results show that symptoms related to an underlying somatic disease are quite diverse and resemble symptoms of a primary psychotic process to a large extent. So there exist no (new) early warning signs. These findings are, crucial as they are mainly in contrast to current common knowledge and make the differential diagnosis even more critical and complex. A further prospective cohort study is necessary in an attempt to create a diagnostic algorithm for psychotic symptoms in children.

[Exercise and fasting induced movement disorder in children: think of the GLUT1 deficiency syndrome]. / Een bewegingsstoornis na inspanning en vasten bij kinderen.

BACKGROUND: Glucose transporter type 1 (GLUT1) enables glucose to pass through the blood-brain barrier. A hereditary deficiency of this protein may lead to clinical symptoms when blood glucose levels are decreasing. CASE DESCRIPTION: A 7-year-old girl with therapy-resistant childhood absence epilepsy presented with an exercise and fasting induced dystonic and atactic movement pattern. The movement pattern disappears postprandial. Based on a reduced glucose in the liquor, and also a reduced liquor glucose/serum glucose ratio, the diagnosis of GLUT1 deficiency syndrome was considered. Through genetic diagnostics a mutation of the SLC2A1 gene was identified, thereby confirming the initial diagnosis. The patient was referred to a tertiary centre for advice on following a ketogenic diet. After initiation of this treatment she no longer experienced absence epilepsy or paroxysmal dyskinesia episodes. CONCLUSION: GLUT1 deficiency syndrome is a relatively underdiagnosed disease. The recommended therapy is adherence to a ketogenic diet. With this diet the symptoms are treated, yet at the same time the further development of the brain is stimulated.

Mutations in the Chromatin Regulator Gene BRPF1 Cause Syndromic Intellectual Disability and Deficient Histone Acetylation.

Identification of over 500 epigenetic regulators in humans raises an interesting question regarding how chromatin dysregulation contributes to different diseases. Bromodomain and PHD finger-containing protein 1 (BRPF1) is a multivalent chromatin regulator possessing three histone-binding domains, one non-specific DNA-binding module, and several motifs for interacting with and activating three lysine acetyltransferases. Genetic analyses of fish brpf1 and mouse Brpf1 have uncovered an important role in skeletal, hematopoietic, and brain development, but it remains unclear how BRPF1 is linked to human development and disease. Here, we describe an intellectual disability disorder in ten individuals with inherited or de novo monoallelic BRPF1 mutations. Symptoms include infantile hypotonia, global developmental delay, intellectual disability, expressive language impairment, and facial dysmorphisms. Central nervous system and spinal abnormalities are also seen in some individuals. These clinical features overlap with but are not identical to those reported for persons with KAT6A or KAT6B mutations, suggesting that BRPF1 targets these two acetyltransferases and additional partners in humans. Functional assays showed that the resulting BRPF1 variants are pathogenic and impair acetylation of histone H3 at lysine 23, an abundant but poorly characterized epigenetic mark. We also found a similar deficiency in different lines of Brpf1-knockout mice. These data indicate that aberrations in the chromatin regulator gene BRPF1 cause histone H3 acetylation deficiency and a previously unrecognized intellectual disability syndrome.

Unilateral macrostomia in the newborn: a rare congenital anomaly of the oral commissure.

Macrostomia is a rare medical condition, defined as an enlargement of the mouth at the oral commissure. The incidence varies between 1 in 60 000 to 1 in 300 000 live births. Macrostomia is a form of a facial cleft. Macrostomia can present as a unilateral or bilateral anomaly with a partial or complete cleft. Associated anomalies of the surrounding bone, muscle and soft tissue can also be present with or without the presence of a syndrome. Macrostomia results in aesthetic disharmony and also in functional problems. In both cases surgery is the treatment of choice. In cases of macrostomia, additional investigations should be performed to rule out accompanying cardiac and renal anomalies and associated syndromes. A multidisciplinary approach and good collaboration between healthcare providers is essential for optimal care of these patients.

Posterior reversible encephalopathy syndrome in paediatric leukaemia.

This report describes four patients with acute lymphoblastic leukaemia, suffering from posterior reversible encephalopathy syndrome during the induction period of treatment. A review of the literature on posterior reversible encephalopathy syndrome in paediatric leukaemia is given. The exact mechanism of posterior reversible encephalopathy syndrome is not clear and seems to be multifactorial. Hypertension is likely to play a major role in the development but could be also secondary. All patients in this case series presented after introduction of the new induction protocol for acute lymphoblastic leukaemia. Treatment of hypertension is likely to have a favourable role and posterior reversible encephalopathy syndrome is most often reversible. It is important to consider this diagnosis during the induction phase of leukaemia treatment in the presence of neurological symptoms. The incidence of PRES in the induction scheme should be investigated, in order to optimize the ALL treatment.

Growth in treated classical galactosemia patients.

Decreased height and weight in treated children with classical galactosemia have been reported. However, growth has not been extensively studied. Patients might be at risk for an abnormal growth because of either disease-related intrinsic factors or diet-related factors. The objective was to gain insight in growth in treated children and adolescents with classical galactosemia. The studied population was a previously reported group of 40 classical galactosemia children. Prenatal growth was evaluated using length, weight and head circumference (HC) data from welfare centers or parents. Postnatal growth was evaluated using three height and weight measurements at baseline, 1 and 2 years to calculate growth velocities. Height Z-score was also corrected for target height Z-score (height Z-score divided by target height Z-score). Linear regression analysis was performed between growth velocities, IGF-I, IGFBP-3, dietary intake and galactose-1-phosphate-uridyltransferase activity. We found normal length (median 50.5 cm), weight (median 3,255 grams) and HC (median 33.9 cm) at birth. Mean height growth velocity was 0.87+/-1.2 for boys and -0.89+/-2.1 for girls, and mean weight growth velocity was 0.91+/-1.6 for boys and -0.74+/-1.3 for girls. Mean height corrected for target height was -1.5+/-0.9 in girls and -0.6+/-0.7 in boys. Height growth velocity was correlated with IGF-I (Pearson correlation= 0.499), IGFBP-3 (Pearson correlation 0.4) and height Z-scores corrected for target height Z-scores (Pearson correlation=0.550). Five children grew beyond the age of 18 years. In conclusion, prenatal growth was normal but postnatal growth was affected. Predicted final height is less than target height in most patients; however, target height might be reached for the children who grow beyond the age of 18. Decreased IGF-I and IGFBP-3 and or suboptimal hormonal replacement in girls might play a role.

The endocrine system in treated patients with classical galactosemia.

Endocrine abnormalities in classical galactosemia, female hypergonadotropic hypogonadism and low thyroxin in neonates, have been reported. Galactosemia is a secondary glycosylation disorder and hypoglycosylation of glycoproteins has a role in this dysfunction. Hypoglycosylation, improves but does not completely disappear with dietary treatment. Our aim was to evaluate the endocrine system in treated patients (n = 37, 25 females, 12 males, age 5-19 years). Endocrine determinations were compared to age and gender matched reference ranges. Sample t-test (to test differences with reference population) and linear regression analysis between hGH (growth hormone), IGF-1 (insulin-like growth factor), IGFBP-3 (insulin growth factor binding protein), FSH (follicle stimulating hormone), LH (luteinizing hormone) and GALT activity, and soy intake, was carried out. Mean IGF-1 Z-score was -0.98 +/- 0.84 (range -2.59 to 1.21) (P < 0.001) in females and 0.03 +/- 0.55 (range -1.0 to 0.89) (P = 0.84) in males. Mean IGFBP-3 Z-score was -0.98 +/- 1.3 (range -3.0 to 2.0) (P < 0.001) in females and 0.26 +/- 0.93 (range -0.94 to 2.0) (P = 0.35) in males. IGF-1 and IGFBP-3 were positively correlated (P < 0.001). IGF-1 or IGFBP-3 Z-scores and age, hGH, estradiol, GALT activity or soy intake were not correlated. FSH was elevated in females, other axes were normal. Besides the hypergonadotropic hypogonadism in females, IGF-1 and IGFBP-3 are in the low to normal ranges in girls. Hypoglycosylation in galactosemia is diet dependent and could worsen when galactose intake increases either because of poor compliance or diet liberalization.

Effect of calcium, vitamins K1 and D3 on bone in galactosemia.

Classical galactosemia is an inherited disorder of galactose metabolism. Recently, diminished bone mineral content (BMC) in children and adolescents has been found. The aim of this study was to evaluate the effect of calcium, vitamins K(1) and D(3) supplementation on bone in children with galactosemia. A 2-year randomized, double-blind, placebo-controlled clinical trial was undertaken in which 40 children with classical galactosemia (13 males and 27 females, aged 3-17 years) were included to receive daily either 750 mg calcium, 1.0 mg vitamin K(1) and 10.0 microg vitamin D(3) or placebo. BMC of femoral neck, lumbar spine and total body and body composition data were determined by dual energy X-ray absorptiometry (DXA) at baseline and after 1 and 2 years. Diet was assessed using a food frequency questionnaire and a 3-day food diary. Biochemical measurements were determined at baseline and after 1 and 2 years. In the children receiving treatment, carboxylated osteocalcin (cOC) concentration significantly increased (P < 0.001) and undercarboxylated osteocalcin (ucOC) concentration significantly decreased (P = 0.001) when compared to the children receiving placebo. Furthermore, there was a statistically significant increase in BMC of lumbar spine (P = 0.001), lean tissue mass (LTM: P = 0.016) and fat mass (FM: P = 0.014) in the treatment group when compared to the placebo group. The significant increase in cOC and decrease in ucOC concentration in the treatment group were present in prepubertal (P < 0.001 and P = 0.006 respectively) and pubertal children (P = 0.004 and P = 0.042 respectively). The significant increase in BMC of lumbar spine in the treatment group was present only in the prepubertal children (P = 0.015). Supplementation of calcium, vitamins K(1) and D(3) given in this dose (750 mg, 1.0 mg and 10.0 mug respectively) is likely to have a role in the treatment of BMC abnormalities in galactosemia.

Untreated classical galactosemia patient with mild phenotype.

Despite life-long galactose restriction, long-term complications generally occur in classical galactosemia. We report an adult male with classical galactosemia (Q188R homozygosity, severely reduced erythrocyte galactose-1-phosphate uridyltransferase activity) who has a surprisingly mild phenotype despite genotype and enzyme activity associated with severe phenotype. Moreover he has a normal galactose intake from the age of 3 years. This case is probably an example of the important role of yet unknown susceptibility and or modifier genes.