Variants in CUL4B are Associated with Cerebral Malformations

Variants in cullin 4B (CUL4B) are a known cause of syndromic X-linked intellectual disability. Here, we describe an additional 25 patients from 11 families with variants in CUL4B. We identified nine different novel variants in these families and confirmed the pathogenicity of all nontruncating variants. Neuroimaging data, available for 15 patients, showed the presence of cerebral malformations in ten patients. The cerebral anomalies comprised malformations of cortical development (MCD), ventriculomegaly, and diminished white matter volume. The phenotypic heterogeneity of the cerebral malformations might result from the involvement of CUL-4B in various cellular pathways essential for normal brain development. Accordingly, we show that CUL-4B interacts with WDR62, a protein in which variants were previously identified in patients with microcephaly and a wide range of MCD. This interaction might contribute to the development of cerebral malformations in patients with variants in CUL4B

MR Imaging and Proton MR Spectroscopic Studies in Sjögren-Larsson Syndrome: Characterization of the Leukoencephalopathy

BACKGROUND AND PURPOSE: Sjögren-Larsson syndrome (SLS) is a neurocutaneous syndrome caused by a genetic enzyme deficiency in lipid metabolism. Our purpose was to characterize the nature of the cerebral involvement in SLS. METHODS: MR imaging was performed in 18 patients (aged 5 months to 45 years) and repeated in 14. Single-voxel proton MR spectra were acquired from cerebral white matter and gray matter in 16 patients, with follow-up studies in 11. LCModel fits were used to determine brain metabolite levels. RESULTS: MR imaging showed retardation of myelination and a mild persistent myelin deficit. A zone of increased signal intensity was seen in the periventricular white matter on T2-weighted images. Proton MR spectroscopy of white matter revealed a prominent peak at 1.3 ppm, normal levels of N-acetylaspartate, and elevated levels of creatine (+14%), choline (+18%), and myo-inositol (+54%). MR imaging and proton MR spectroscopy of gray matter were normal. In the two patients examined during the first years of life, abnormalities on MR imaging and proton MR spectroscopy gradually emerged and then stabilized, as in all other patients. CONCLUSION: Abnormalities on MR imaging and proton MR spectroscopy emerge during the first years of life and are similar in all patients with SLS, but the severity varies. The changes are confined to cerebral white matter and suggest an accumulation of lipids, periventricular gliosis, delayed myelination, and a mild permanent myelin deficit

Mutations in the ALDH7A1 gene cause pyridoxine-dependent seizures

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Heterozygous NOTCH1 variants cause CNS immune activation and microangiopathy

NOTCH1 belongs to the NOTCH family of proteins that regulate cell fate and inflammatory responses. Somatic and germline NOTCH1 variants have been implicated in cancer, Adams-Oliver syndrome, and cardiovascular defects. We describe 7 unrelated patients grouped by the presence of leukoencephalopathy with calcifications and heterozygous de novo gain-of-function variants in NOTCH1. Immunologic profiling showed upregulated CSF IP-10, a cytokine secreted downstream of NOTCH1 signaling. Autopsy revealed extensive leukoencephalopathy and microangiopathy with vascular calcifications. This evidence implicates that heterozygous gain-of-function variants in NOTCH1 lead to a chronic central nervous system (CNS) inflammatory response resulting in a calcifying microangiopathy with leukoencephalopathy. ANN NEUROL 2022;92:895–901

Neuropeptide changes and neuroactive amino acids in CSF from humans and sheep with neuronal ceroid lipofuscinoses (NCLs, Batten disease).

Item does not contain fulltextAnomalies in neuropeptides and neuroactive amino acids have been postulated to play a role in neurodegeneration in a variety of diseases including the inherited neuronal ceroid lipofuscinoses (NCLs, Batten disease). These are often indicated by concentration changes in cerebrospinal fluid (CSF). Here we compare CSF neuropeptide concentrations in patients with the classical juvenile CLN3 form of NCL and the classical late infantile CLN2 form with neuropeptide and neuroactive amino acid concentrations in CSF from sheep with the late infantile variant CLN6 form. A marked disease related increase in CSF concentrations of neuron specific enolase and tau protein was noted in the juvenile CLN3 patients but this was not observed in an advanced CLN2 patient nor CLN6 affected sheep. No changes were noted in S-100b, GFAP or MBP in patients or of S-100b, GFAP or IGF-1 in affected sheep. There were no disease related changes in CSF concentrations of the neuroactive amino acids, aspartate, glutamate, serine, glutamine, glycine, taurine and GABA in these sheep. The changes observed in the CLN3 patients may be progressive markers of neurodegeneration, or of underlying metabolic changes perhaps associated with CLN3 specific changes in neuroactive amino acids, as have been postulated. The lack of changes in the CLN2 and CLN6 subjects indicate that these changes are not shared by the CLN2 or CLN6 forms and changes in CSF concentrations of these compounds are unreliable as biomarkers of neurodegeneration in the NCLs in general

Mutations in MED12 Cause X-Linked Ohdo Syndrome

<p>Ohdo syndrome comprises a heterogeneous group of disorders characterized by intellectual disability (ID) and typical facial features, including blepharophimosis. Clinically, these blepharophimosis-ID syndromes have been classified in five distinct subgroups, including the Maat-Kievit-Brunner (MKB) type, which, in contrast to the others, is characterized by X-linked inheritance and facial coarsening at older age. We performed exome sequencing in two families, each with two affected males with Ohdo syndrome MKB type. In the two families, MED12 missense mutations (c.3443G>A [p.Arg1148His] or c.3493T>C [p.Ser1165Pro]) segregating with the phenotype were identified. Upon subsequent analysis of an additional cohort of nine simplex male individuals with Ohdo syndrome, one additional de novo missense change (c.5185C>A [p.His1729Asn]) in MED12 was detected. The occurrence of three different hemizygous missense mutations in three unrelated families affected by Ohdo syndrome MKB type shows that mutations in MED12 are the underlying cause of this X-linked form of Ohdo syndrome. Together with the recently described KAT6B mutations resulting in Ohdo syndrome Say/Barber/Biesecker/Young/Simpson type, our findings point to aberrant chromatin modification as being central to the pathogenesis of Ohdo syndrome.</p>

Variants in CUL4B are Associated with Cerebral Malformations

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