Impaired Amino Acid Transport at the Blood Brain Barrier Is a Cause of Autism Spectrum Disorder.

Autism spectrum disorders (ASD) are a group of genetic disorders often overlapping with other neurological conditions. We previously described abnormalities in the branched-chain amino acid (BCAA) catabolic pathway as a cause of ASD. Here, we show that the solute carrier transporter 7a5 (SLC7A5), a large neutral amino acid transporter localized at the blood brain barrier (BBB), has an essential role in maintaining normal levels of brain BCAAs. In mice, deletion of Slc7a5 from the endothelial cells of the BBB leads to atypical brain amino acid profile, abnormal mRNA translation, and severe neurological abnormalities. Furthermore, we identified several patients with autistic traits and motor delay carrying deleterious homozygous mutations in the SLC7A5 gene. Finally, we demonstrate that BCAA intracerebroventricular administration ameliorates abnormal behaviors in adult mutant mice. Our data elucidate a neurological syndrome defined by SLC7A5 mutations and support an essential role for the BCAA in human brain function.

Bi-allelic Mutations in FAM149B1 Cause Abnormal Primary Cilium and a Range of Ciliopathy Phenotypes in Humans.

Ciliopathies are clinical disorders of the primary cilium with widely recognized phenotypic and genetic heterogeneity. In two Arab consanguineous families, we mapped a ciliopathy phenotype that most closely matches Joubert syndrome (hypotonia, developmental delay, typical facies, oculomotor apraxia, polydactyly, and subtle posterior fossa abnormalities) to a single locus in which a founder homozygous truncating variant in FAM149B1 was identified by exome sequencing. We subsequently identified a third Arab consanguineous multiplex family in which the phenotype of Joubert syndrome/oral-facial-digital syndrome (OFD VI) was found to co-segregate with the same founder variant in FAM149B1. Independently, autozygosity mapping and exome sequencing in a consanguineous Turkish family with Joubert syndrome highlighted a different homozygous truncating variant in the same gene. FAM149B1 encodes a protein of unknown function. Mutant fibroblasts were found to have normal ciliogenesis potential. However, distinct cilia-related abnormalities were observed in these cells: abnormal accumulation IFT complex at the distal tips of the cilia, which assumed bulbous appearance, increased length of the primary cilium, and dysregulated SHH signaling. We conclude that FAM149B1 is required for normal ciliary biology and that its deficiency results in a range of ciliopathy phenotypes in humans along the spectrum of Joubert syndrome.

SIL1 mutations and clinical spectrum in patients with Marinesco-Sjogren syndrome.

Marinesco-Sjögren syndrome is a rare autosomal recessive multisystem disorder featuring cerebellar ataxia, early-onset cataracts, chronic myopathy, variable intellectual disability and delayed motor development. More recently, mutations in the SIL1 gene, which encodes an endoplasmic reticulum resident co-chaperone, were identified as the main cause of Marinesco-Sjögren syndrome. Here we describe the results of SIL1 mutation analysis in 62 patients presenting with early-onset ataxia, cataracts and myopathy or combinations of at least two of these. We obtained a mutation detection rate of 60% (15/25) among patients with the characteristic Marinesco-Sjögren syndrome triad (ataxia, cataracts, myopathy) whereas the detection rate in the group of patients with more variable phenotypic presentation was below 3% (1/37). We report 16 unrelated families with a total of 19 different SIL1 mutations. Among these mutations are 15 previously unreported changes, including single- and multi-exon deletions. Based on data from our screening cohort and data compiled from the literature we found that SIL1 mutations are invariably associated with the combination of a cerebellar syndrome and chronic myopathy. Cataracts were observed in all patients beyond the age of 7 years, but might be missing in infants. Six patients with SIL1 mutations had no intellectual disability, extending the known wide range of cognitive capabilities in Marinesco-Sjögren syndrome to include normal intelligence. Modestly constant features were somatic growth retardation, skeletal abnormalities and pyramidal tract signs. Examination of mutant SIL1 expression in cultured patient lymphoblasts suggested that SIL1 mutations result in severely reduced SIL1 protein levels irrespective of the type and position of mutations. Our data broaden the SIL1 mutation spectrum and confirm that SIL1 is the major Marinesco-Sjögren syndrome gene. SIL1 patients usually present with the characteristic triad but cataracts might be missing in young children. As cognitive impairment is not obligatory, patients without intellectual disability but a Marinesco-Sjögren syndrome-compatible phenotype should receive SIL1 mutation analysis. Despite allelic heterogeneity and many families with private mutations, the phenotype related to SIL1 mutations is relatively homogenous. Based on SIL1 expression studies we speculate that this may arise from a uniform effect of different mutations on protein expression.

Cerebral sinovenous thrombosis associated with MTHFR A1298C mutation in the newborn: a case report.

Although cerebral sinovenous thrombosis (CSVT) is a rare condition in the neonatal period, high rates of morbidity and mortality necessitate the establishment of an early diagnosis. Methylenetetrahydrofolate reductase (MTHFR) plays a central role in the folate cycle and mutations of MTHFR are associated with vascular disease. While the C677T common missense mutation is the most well-defined MTHFR polymorphism, another common missense mutation, A1298C also exists. There has been no reported case of CSVT associated with MTHFR A1298C mutation in the neonatal period. Herein, we report a neonate with CSVT who was found to have MTHFR A1298C homozygosity.

TRAPPC9-Related Intellectual Disability: Report of Two New Cases and Review of the Literature.

Introduction: Hereditary forms of intellectual disability (ID), an estimated prevalence ranging between 1% and 3% in the general population, are among the most important problems in health care. Especially, autosomal-recessive ID has a very heterogeneous molecular basis and a lack of specific phenotypic features. Methods: Here, we report on two unrelated patients with autosomal-recessive ID, microcephaly, and autistic features and review the patients with TRAPPC9-related ID. Whole-exome sequencing and array CGH were performed for molecular diagnosis of the patients. Results: The first case has a microdeletion on chromosome 8q24.23-q24.3 region which is 1.7 Mb in length and includes the last 5 exons of TRAPPC9, and c.3435delG [p.Thr1146Profs*8] deletion. The second case has a homozygous missense c.623A>C (p.His208Pro) variant in TRAPPC9 which is detected by means of whole-exome sequencing study of the proband. We also reviewed the clinical findings and mutation spectrum of all patients with TRAPPC9-related ID reported so far. Conclusions: Our study showed that the most consistent clinical findings for TRAPPC9-related ID are ID, microcephaly, and some structural brain MRI abnormalities. The mutations in the TRAPPC9 are scattered throughout all exons of TRAPPC9 indicating there is no hot spot mutation region in this gene.

Effects of treatment with clinically relevant valproate, carbamazepine, oxcarbazepine, topiramate, lamotrigine and levetiracetam on ovarian folliculogenesis in young rats.

AIM: To determine the effects of valproate (VPA), carbamazepine (CBZ), oxcarbazepine (OXC), topiramate (TPM), lamotrigine (LTG), and levetiracetam (LEV) on ovarian folliculogenesis in young rats. METHODS: Forty-nine female Wistar rats, aged 21-24 days, were divided equally into 7 experimental groups. These were given tap water over 21-24 days (control group), 300 mg/kg of VPA, 150 mg/kg of CBZ, 150 mg/kg of OXC, 100 mg/kg of TPM, 10 mg/kg of LTG, or 50 mg/kg of LEV daily in 2 doses via oral gavage until the end of puberty. At the end of the study, the estrous cycle of each rat was monitored daily, and those rats in pro-estrus or di-estrus were sacrificed and the ovaries removed. Serial sections obtained from the ovaries were stained with hematoxylin and eosin, and the corpora lutea and follicles were enumerated. Apoptotic cells were detected using the TUNEL technique. Various serial sections were immunohistochemically stained with proliferating cell nuclear antigen (PCNA), growth differentiation factor (GDF)-9, caspase-3, caspase-9, transforming growth factor beta 1 (TGF-1), and epidermal growth factor (EGF), and evaluated and photographed under a light microscope. KEY FINDINGS: The number of corpora lutea was significantly increased in the VPA, CBZ, OXC, and LTG groups compared to the control group (p < 0.001). The number of TUNEL-positive ovarian follicles was 3.3 ± 1.1 (median, 3), 6.1 ± 0.9 (median, 6), and 5.7 ± 0.8 (median,6) in the control, OXC and LEV groups, respectively (p < 0.001). The number of TUNEL-positive granulosa cells was higher in all the groups treated with antiepileptics, with the exception of the TPM group, compared to the control group (p < 0.001). HSCOREs for immunohistochemical staining using PCNA, GDF-9, TGF-1 and EGF were significantly higher in the control group than in the others (p < 0.001). HSCORE for staining using caspase-3 was significantly higher in the VPA, CBZ, OXC and LEV groups, while the HSCORE was significantly lower in the TPM group than in the control group. HSCORE for staining using caspase-9 was significantly higher in the VPA, CBZ and OXC groups, while it was significantly lower in the TPM group than in the control group (p < 0.001). SIGNIFICANCE: Exposure to VPA, CBZ, OXC, TPM, LTG and LEV caused different levels of impaired folliculogenesis in young rats.

SLC35A2-CDG: novel variants with two ends of the spectrum.

OBJECTIVES: Congenital disorders of glycosylation (CDGs) are rare inherited metabolic disorders associated with facial dysmorphism and in the majority of the patients, there is an important neurological impairment. Epilepsy was a main concern in rare forms of the disease. There are two groups of the disease: CDG-I results from the defects in glycan addition to the N-terminal and CDG-II occurs due to defects in the processing of protein bound glycans. SLC35A2-CDG is a rare form of CDG caused by mutations in the X-linked gene that encodes a UDP-Galactose transporter. The manifestations of the disease include seizures, failure to thrive, delayed myelination, and cerebral atrophy. CASE PRESENTATION: We describe herein a severe female child with intractable seizures, microcephaly, growth retardation, hypotonia, global developmental delay, facial dysmorphism, skeletal findings, cerebral/cerebellar atrophy, and thin corpus callosum, and a mildly affected male carrying a novel variant with seizures and mild global developmental delay who were found by whole exome sequencing (WES) for SLC35A2 mutations previously not reported. CONCLUSIONS: Our findings expand the number of reported cases and add novel variants to the repertoire of SLC35A2-CDG.

Coexistence of guanidinoacetate methyltransferase (GAMT) deficiency and neuroleptic malignant syndrome without creatine kinase elevation.

We describe the first child with guanidinoacetate methyltransferase (GAMT) deficiency who developed neuroleptic malignant syndrome (NMS) after the treatment of risperidone without elevated creatine kinase (CK) levels. The patient presented with lethargy, hyperthermia, generalized tremor and rigidity with normal serum CK levels. After cessation of risperidone and adding clonezepam to the supportive treatment, symptoms of NMS were ameliorated. We conclude that although serum CK elevation is a useful indicator for the early detection of NMS, normal serum CK levels may be seen during the NMS course in the presence of GAMT deficiency.

MINPP1 prevents intracellular accumulation of the chelator inositol hexakisphosphate and is mutated in Pontocerebellar Hypoplasia.

Inositol polyphosphates are vital metabolic and secondary messengers, involved in diverse cellular functions. Therefore, tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, we describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the multiple inositol-polyphosphate phosphatase 1 gene (MINPP1). Patients are found to have a distinct type of Pontocerebellar Hypoplasia with typical basal ganglia involvement on neuroimaging. We find that patient-derived and genome edited MINPP1-/- induced stem cells exhibit an inefficient neuronal differentiation combined with an increased cell death. MINPP1 deficiency results in an intracellular imbalance of the inositol polyphosphate metabolism. This metabolic defect is characterized by an accumulation of highly phosphorylated inositols, mostly inositol hexakisphosphate (IP6), detected in HEK293 cells, fibroblasts, iPSCs and differentiating neurons lacking MINPP1. In mutant cells, higher IP6 level is expected to be associated with an increased chelation of intracellular cations, such as iron or calcium, resulting in decreased levels of available ions. These data suggest the involvement of IP6-mediated chelation on Pontocerebellar Hypoplasia disease pathology and thereby highlight the critical role of MINPP1 in the regulation of human brain development and homeostasis.

A novel mutation in two cousins with guanidinoacetate methyltransferase (GAMT) deficiency presented with autism.

Aydin HI, Sönmez FM. A novel mutation in two cousins with guanidinoacetate methyltransferase (GAMT) deficiency presented with autism. Turk J Pediatr 2019; 61: 92-96. Guanidinoacetate methyltransferase (GAMT) deficiency is a rare autosomal recessive disorder of creatine biosynthesis. Here, we report 9 and 10-year-old cousins with GAMT deficiency caused by a novel mutation who both exhibited neurodevelopmental retardation, seizures, behavioral problems, and autism that began during early infancy. The patients were diagnosed as having only autism and followed for years without a specific diagnosis although they had very low levels of serum creatinine for several times. A novel nonsense mutation in the GAMT gene that caused cessation of synthesis of the protein encoded by this gene was identified in these patients. GAMT deficiency is a treatable inborn error of metabolism and should be considered for all patients with hypotonia, developmental delay, seizures and autism, particularly if low serum creatinine levels are observed.

Atypical presentations of SSPE: a clinical study in four cases.

Subacute sclerosing panencephalitis (SSPE) is a progressive, fatal disease of the central nervous system caused by a persistent measles virus. It is clinically characterized by insidious onset of intellectual deterioration and behavioral changes followed by myoclonias and eventually complete neurologic deterioration. The diagnosis is based on characteristic clinical features, periodic electroencephalography (EEG) complexes of high slow waves and increased antibody titer against measles in cerebrospinal fluid. Here, we report four SSPE cases, two of whom manifested with hemiparesis; in the third and fourth cases, cerebellar ataxia and acute encephalopathy with focal seizures were the presenting symptoms at the onset of disease, respectively. The typical periodic EEG complexes in our patients led to the diagnosis of SSPE. Our findings show that SSPE should be considered in the differential diagnosis of hemiparesis, cerebellar ataxia and acute encephalopathy, and highlight the diagnostic significance of EEG in unidentified cases.

Microdeletion of chromosome 1q21.3 in fraternal twins is associated with mental retardation, microcephaly, and epilepsy.

Reported here are twins, both of whom have a 1q21.3 microdeletion and who exhibit key features common to previously reported cases such as microcephaly and developmental delay. However, some clinical findings and deleted genes differed from those in previously reported cases. The karyotype was normal 46, XX for both of the twins. Array comparative genomic hybridization (CGH) identified a 2.6 Mb deletion on chromosome 1q21.3 (chr1: 153,514,121-156,171,335 bp) in case 1 and a 1.6 Mb deletion on chromosome 1q21.3 (chr1: 154,748,365-156,358,923 bp) in case 2. The deleted region includes DPM3, MUC1, GBA, PKLR, RIT1, and LAMTOR2 in both siblings. To the extent known, this is the second report of a 1q21.3 microdeletion in a family with mental retardation, developmental delay, seizures, and some dysmorphic features, thus expanding the phenotypic spectrum.

Severe form of Cockayne syndrome with varying clinical presentation and no photosensitivity in a family.

We report six patients with Cockayne syndrome type B without photosensitivity. The patients are from the same inbred family and exhibit variable clinical features. The main clinical manifestations were progressive encephalopathy including intracranial calcification and white-matter lesions, dwarfism without growth hormone deficiency, senile appearance, mental and motor retardation, atrophy of subcutaneous fat tissue, severe pectus carinatus, and spasticity. Clinical photosensitivity was not observed in any patient. Other clinical findings were cataract, pigmentary retinopathy, and peripheral neuropathy. The onset of the disease was between 3 and 6 months of age. Molecular genetic analyses in the family established linkage to ERCC6, the gene responsible for Cockayne syndrome type B, confirming the clinical diagnosis.

Effect of antiepileptic drugs on plasma lipids, lipoprotein (a), and liver enzymes.

We conducted a study to assess the effect of phenobarbital, carbamazepine, and valproate on serum lipid profiles and lipoprotein (a) in 64 children with epilepsy (aged between 1 and 15 years) admitted to the child neurology outpatient clinic between July 2000 and July 2002. The children were separated as group 1 (18 children), treated with phenobarbital, 5 mg/kg/day; group 2 (22 children), treated with carbamazepine, 10 to 15 mg/kg/day; and group 3 (24 children), treated with sodium valproate, 20 mg/kg/day. Plasma lipoprotein (a), total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein A and apolipoprotein B levels, and liver enzymes alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and gamma-glutamyltransferase were determined before the initiation of the treatment and at 3, 6, and 12 months of the treatment period. The mean age of children in group 1 was significantly low compared with those in groups 2 and 3 (P <.05). The mean pretreatment lipid levels among the groups were not significantly increased. The mean lipoprotein (a) levels were significantly increased in all groups at 3, 6, and 12 months of the treatment period (P <.05). The increase in alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol at 3, 6, and 12 months was statistically significant in group 1 (P <.05). The higher levels in lipoprotein (a) (mean > 30 mg/dL) were observed only in carbamazepine-treated patients at 6 and 12 months. The percentage of children with lipoprotein (a) levels over 30 mg/dL was 44%, 63%, and 33% in the phenobarbital-, carbamazepine-, and valproate-treated children, respectively. Antiepileptic drugs significantly increase the level of lipoprotein (a), which is a major risk factor for atherosclerosis, and also have variable effects on other lipid parameters. Lipoprotein (a) levels should be closely followed in patients receiving antiepileptic drugs. (J Child Neurol 2006;21:70-74).

Chromosomal abnormalities in 457 Turkish patients with MCA/MR.

The evaluation of multiple congenital abnormalities and/or mental retardation (MCA/MR) is always a challenge to clinicians. The recognition of specific physical or behavioral characteristics can vastly improve diagnostic yield. Chromosomal abnormalities account for a high percentage in the etiology of MCA/MR. In this study, frequency of chromosomal abnormalities was 4.81% of 457 patients. Chromosomal abnormalities and polymorphisms were detected in 65 (14.21%) (structural and numerical chromosomal abnormalities in 22 patients and polymorphisms in 43) of 457 MR and/or MCA patients. Our results show that chromosomal abnormalities contribute much to the causation of multiple malformations and/or MR. It is essential that fluorescence in situ hybridization (FISH) be used in conjunction with standard methods in order to maximize obtainable information for better management of patients with MR and/or MCA.

Coffin-Siris syndrome with café-au-lait spots, obesity and hyperinsulinism caused by a mutation in the ARID1B gene.

Coffin-Siris syndrome (CSS) (MIM 135900) is characterized by developmental delay, severe speech impairment, distinctive facial features, hypertrichosis, aplasia or hypoplasia of the distal phalanx or nail of the fifth digit and agenesis of the corpus callosum. Recently, it was shown that mutations in the ARID1B gene are the main cause of CSS, accounting for 76% of identified mutations. Here, we report a 15 year-old female patient who was admitted to our clinic with seizures, speech problems, dysmorphic features, bilaterally big, large thumb, café-au-lait (CAL) spots, obesity and hyperinsulinism. First, the patient was thought to have an association of neurofibromatosis and Rubinstein Taybi syndrome. Because of the large size of the NF1 gene for neurofibromatosis and CREBBP gene for Rubinstein Taybi syndrome, whole exome sequence analysis (WES) was conducted and a novel ARID1B mutation was identified. The proband WES test identified a novel heterozygous frameshift mutation c.3394_3395insTA in exon 13 of ARID1B (NM_017519.2) predicting a premature stop codon p.(Tyr1132Leufs*67). Sanger sequencing confirmed the heterozygous c.3394_3395insTA mutation in the proband and that it was not present in her parents indicating de novo mutation. Further investigation and new cases will help to understand this phenomenon better.

Vitamin D Deficiency in Children With Newly Diagnosed Idiopathic Epilepsy.

Several studies have shown a link between vitamin D deficiency and epilepsy. This study includes 60 newly diagnosed idiopathic epilepsy patients and 101 healthy controls (between the ages of 5 and 16). Each group was also divided into two subgroups according to seasonal changes in terms of months of longer versus shorter daylight. We retrospectively evaluated the levels of calcium, phosphorus, alkaline phosphatase, parathyroid hormone, and 25-OH vitamin-D3 in the study participants. Levels below 20 ng/ml were defined as vitamin D deficiency and levels of 20-30 ng/ml as insufficiency. There were no significant differences in age, gender distribution and levels of calcium, phosphorus, alkaline phosphatase and parathyroid hormone between the groups. The level of 25-OH vitamin-D3 in the patient group was significantly lower when compared to the control group (p < 0.05) (14.07 ± 8.12 and 23.38 ± 12.80 ng/ml, respectively). This difference also held true when evaluation was made according to seasonal evaluation (12.38 ± 6.53 and 17.64 ± 1.14 in shorter daylight and 18.71 ± 9.87 and 30.82 ± 1.04 in longer daylight).

Retrospective evaluation of interferon-beta treatment in subacute sclerosing panencephalitis.

BACKGROUND: Few effective treatment methods are available for subacute sclerosing panencephalitis (SSPE),an infection associated with the measles virus. Interferons have shown some benefit in previous studies and clinical practice. OBJECTIVE: The purpose of this study was to compare the efficacy of 2 different regimens of interferon-beta(IFN-beta) in the treatment of SSPE in pediatric patients. METHODS: We retrospectively compared the results obtained with 2 regimens of IFN-beta1a: 60 microg administered intramuscularly once weekly (IFN-beta 1/wk), or 22 microg administered subcutaneously 3 times per week (IFN-beta 3/wk). All patients also received oral inosiplex 50 to 100 mg/kg daily, a treatment known to have partial efficacy in SSPE. Patients who continued treatment for at least 3 months and had at least 1 year of follow-up data were evaluated. Clinical parameters included the Neurological Disability Index (NDI), a measurement of mental, motor, and sensory functions; disease stage; and mental status. Data obtained at 6 and 12 months were compared with those at the time of diagnosis, and the percent change from baseline was calculated. A satisfactory clinical response was defined as reduction or stabilization of the NDI or stage improvement at 6 or 12 months. RESULTS: Patients treated with IFN-beta 3/wk had increased survival time (P < 0.02) and higher clinical response rates compared with those treated with IFN-beta 1/wk (P < 0.05). When stage 2 and stage 3 patients were evaluated separately, survival was significantly longer (P = 0.007) and the rate of progression slower in both stage groups with IFN-beta 3/wk. CONCLUSION: The results obtained for this patient sample suggest that IFN-beta administered subcutaneously times per week combined with inosiplex may be an effective treatment option in SSPE. This treatment regimen warrants further study.

Brainstem encephalitis and acute disseminated encephalomyelitis following mumps.

A previously healthy female, aged 4 years 3 months, developed brainstem encephalitis with clinical manifestations of fever, decreased level of consciousness, and left facial and abducens paralysis 1 week after bilateral parotitis. Twenty days after remission of encephalitis, she manifested new symptoms of ataxia, dysarthria, and fever. Magnetic resonance imaging revealed multiple hyperintense lesions which were increased in size when compared with the first magnetic resonance imaging. She was treated with glucocorticoids and intravenous immunoglobulin. Forty-eight days after therapy, she was able to walk with support and recovered completely on follow-up. Brainstem encephalitis and acute disseminating encephalomyelitis are discussed as rare complications of mumps.