Cell reprogramming promises to make characterization of the impact of human genetic variation on health and disease experimentally tractable by enabling the bridging of genotypes to phenotypes in ...developmentally relevant human cell lineages. Here we apply this paradigm to two disorders caused by symmetrical copy number variations of 7q11.23, which display a striking combination of shared and symmetrically opposite phenotypes--Williams-Beuren syndrome and 7q-microduplication syndrome. Through analysis of transgene-free patient-derived induced pluripotent stem cells and their differentiated derivatives, we find that 7q11.23 dosage imbalance disrupts transcriptional circuits in disease-relevant pathways beginning in the pluripotent state. These alterations are then selectively amplified upon differentiation of the pluripotent cells into disease-relevant lineages. A considerable proportion of this transcriptional dysregulation is specifically caused by dosage imbalances in GTF2I, which encodes a key transcription factor at 7q11.23 that is associated with the LSD1 repressive chromatin complex and silences its dosage-sensitive targets.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UILJ, UKNU, UL, UM, UPUK
Intestinal lymphangiectasia (IL) is a rare disease characterized by dilatation and rupture of intestinal lymphatic channels leading to protein-losing enteropathy. IL is classified as primary and ...secondary types.
A 3-month-old girl born at term from vaginal delivery with an APGAR score of 10/10 and birth weight of 4.310 g (>97° percentile) was admitted to our hospital because of increasing abdominal tenderness and diarrhea. At first examination, she presented an abdominal circumference of 60 cm, edema of the lower extremities and vulva, and facial dysmorphisms (hypertelorism, flat nasal bridge, flat mid-face).
Once admitted, ultrasonography showed a large amount of ascites, while blood laboratory investigations revealed severe hypoproteinemia, hypoalbuminemia and hypogammaglobulinemia. Lymphoscintigraphy with 99m-Tc-nanocolloid demonstrated abnormal leakage of the tracer in the abdomen as evidence of IL. To detect a possible secondary, exams were performed and demonstrated positive antibody titres for CMV-IgM and IgG in blood and CMV-DNA positivity in blood, urine, saliva, maternal milk, and gastric and duodenal biopsies. Genetic investigations identified the genomic variant c.472C>T of the CCBE1 gene, coding for a protein variant (p.Arg158Cys), in homozygosity.
Total parenteral nutrition was started and continued for a total of 18 days, then gradually bridged by enteral nutrition with a special formula. In addition, antiviral therapy for CMV infection was added first with intravenous ganciclovir for 14 days, resulting in the disappearance of blood viral load after 7 days of therapy and then with valganciclovir per os for another 30 days.
The clinical course of the child gradually improved. A few days after starting treatments, lower extremities and vulvar edema disappeared, and abdominal circumference gradually decreased to a stable value of 38 cm, without any ultrasonographic signs of ascites left. Moreover, serum albumin and IgG rose to normal values after 3 months (4.3 g/dL and 501 mg/dL, respectively).
This case suggests that in presence of IL both primary and secondary causes should be evaluated. On the other hand, genetic diagnosis is crucial not only for diagnosis but also for prognosis in HS. Life expectancy and quality could deeply vary among different gene mutations and protein variants of the same gene. Further studies and case reports are needed to better understand the clinical meaning of these genetic results and the role of CMV as trigger of IL.
Abstract
Mutations in the WFS1 gene, encoding wolframin (WFS1), cause endoplasmic reticulum (ER) stress and are associated with a rare autosomal-recessive disorder known as Wolfram syndrome (WS). WS ...is clinically characterized by childhood-onset diabetes mellitus, optic atrophy, deafness, diabetes insipidus and neurological signs. We identified two novel WFS1 mutations in a patient with WS, namely, c.316-1G > A (in intron 3) and c.757A > T (in exon 7). Both mutations, located in the N-terminal region of the protein, were predicted to generate a truncated and inactive form of WFS1. We found that although the WFS1 protein was not expressed in peripheral blood mononuclear cells (PBMCs) of the proband, no constitutive ER stress activation could be detected in those cells. In contrast, WS proband’s PBMCs produced very high levels of proinflammatory cytokines (i.e. TNF-α, IL-1β, and IL-6) in the absence of any stimulus. WFS1 silencing in PBMCs from control subjects by means of small RNA interference also induced a pronounced proinflammatory cytokine profile. The same cytokines were also significantly higher in sera from the WS patient as compared to matched healthy controls. Moreover, the chronic inflammatory state was associated with a dominance of proinflammatory T helper 17 (Th17)-type cells over regulatory T (Treg) lymphocytes in the WS PBMCs. The identification of a state of systemic chronic inflammation associated with WFS1 deficiency may pave the way to innovative and personalized therapeutic interventions in WS.
Abstract CDKL5 deficiency disorder (CDD) is a complex clinical condition resulting from non-functional or absent CDKL5 protein, a serine–threonine kinase pivotal for neural maturation and ...synaptogenesis. The disorder manifests primarily as developmental epileptic encephalopathy, with associated neurological phenotypes, such as hypotonia, movement disorders, visual impairment, and gastrointestinal issues. Its prevalence is estimated at 1 in 40,000–60,000 live births, and it is more prevalent in females due to the lethality of germline mutations in males during fetal development. This Italian multi-center observational study focused on 34 patients with CDKL5-related epileptic encephalopathy, aiming to enhance the understanding of the clinical and molecular aspects of CDD. The study, conducted across 14 pediatric neurology tertiary care centers in Italy, covered various aspects, including phenotypic presentations, seizure types, EEG patterns, treatments, neuroimaging findings, severity of psychomotor delay, and variant-phenotype correlations. The results highlighted the heterogeneity of seizure patterns, with hypermotor-tonic-spasms sequence seizures (HTSS) noted in 17.6% of patients. The study revealed a lack of clear genotype–phenotype correlation within the cohort. The presence of HTSS or HTSS-like at onset resulted a negative prognostic factor for the presence of daily seizures at long-term follow-up in CDD patients. Despite extensive polypharmacotherapy, including medications such as valproic acid, clobazam, cannabidiol, and others, sustained seizure freedom proved elusive, affirming the inherent drug-resistant nature of CDD. The findings underscored the need for further research to explore response rates to different treatments and the potential role of non-pharmacological interventions in managing this challenging disorder.
Triple X syndrome, is an often undiagnosed chromosomal abnormality with an incidence of 1/1000 females. Main associated disorders are urogenital malformations, premature ovarian failure or primary ...amenorrhea, gastrointestinal problems, psychiatric disorders and epilepsy. To date, triple X is not related to a specific epileptic syndrome. Therefore, the purpose of this clinical series is to analyze seizure semiology, electroencephalogram features and the long-term outcome of 13 patients with epilepsy and triple X syndrome.
We retrospectively evaluated the long-term seizure outcome in patients with triple X syndrome who had been referred to 11 Epilepsy Centers in Italy. A close electroclinical follow-up was made for at least 2 years and outcomes were reported.
Our case series confirms that epilepsy is not an occasional finding but part of the phenotypic spectrum of this syndrome. The seizure semiology shows an higher prevalence of focal seizures in 62% of patients. EEG findings of focal epileptic activity were reported in 85% of patients. Anti-seizure medications were successful in all our patients whom in most cases were responsive to monotherapy.
According to our case series most successful drugs were VPA and LEV. Long term prognosis of epilepsy in our case series was good. Our experience suggests that all triple X patients achieve good seizure control and in 69% of cases normalization of the EEG.
To describe the clinical and genetic findings in a cohort of individuals with bathing epilepsy, a rare form of reflex epilepsy.
We investigated by Sanger and targeted resequencing the
gene in 12 ...individuals from 10 different families presenting with seizures triggered primarily by bathing or showering. An additional 12 individuals with hot-water epilepsy were also screened.
In all families with bathing epilepsy, we identified 8 distinct pathogenic or likely pathogenic variants and 2 variants of unknown significance in
, 9 of which are novel. Conversely, none of the individuals with hot-water epilepsy displayed
variants. In mutated individuals, seizures were typically triggered by showering or bathing regardless of the water temperature. Additional triggers included fingernail clipping, haircutting, or watching someone take a shower. Unprovoked seizures and a variable degree of developmental delay were also common.
Bathing epilepsy is genetically distinct reflex epilepsy caused mainly by
mutations.
Despite the known causality of copy-number variations (CNVs) to human neurodevelopmental disorders, the mechanisms behind each gene’s contribution to the constellation of neural phenotypes remain ...elusive. Here, we investigated the 7q11.23 CNV, whose hemideletion causes Williams syndrome (WS), and uncovered that mitochondrial dysfunction participates in WS pathogenesis. Dysfunction is facilitated in part by the 7q11.23 protein DNAJC30, which interacts with mitochondrial ATP-synthase machinery. Removal of Dnajc30 in mice resulted in hypofunctional mitochondria, diminished morphological features of neocortical pyramidal neurons, and altered behaviors reminiscent of WS. The mitochondrial features are consistent with our observations of decreased integrity of oxidative phosphorylation supercomplexes and ATP-synthase dimers in WS. Thus, we identify DNAJC30 as an auxiliary component of ATP-synthase machinery and reveal mitochondrial maladies as underlying certain defects in brain development and function associated with WS.
Display omitted
•Systems biology analyses reveal mitochondrial contribution to 7q11.23 CNV syndromes•The 7q11.23 protein DNAJC30 facilitates ATP synthesis in neocortical neurons•Altered behavior and mitochondrial and neuronal physiomorphology in Dnajc30−/− mice•Deficient mitochondrial function and OXPHOS architecture in WS cells and brains
Reduced copy number of DNAJC30, now shown to interact with the mitochondrial ATP synthase, leads to mitochondrial dysfunction underlying neuronal defects in Williams syndrome.
Elevated fetal hemoglobin (HbF) ameliorates the clinical severity of hemoglobinopathies such as β-thalassemia and sickle cell anemia. Currently, the only curative approach for individuals under ...chronic transfusion/chelation support therapy is allogeneic stem cell transplantation. However, recent analyses of heritable variations in HbF levels have provided a new therapeutic target for HbF reactivation: the transcriptional repressor BCL11A. Erythroid-specific BCL11A abrogation is now actively being sought as a therapeutic avenue, but the specific impact of such disruption in humans remains to be determined. Although single nucleotide polymorphisms in BCL11A erythroid regulatory elements have been reported, coding mutations are scarcer. It is thus of great interest that patients have recently been described with microdeletions encompassing BCL11A. These patients display neurodevelopmental abnormalities, but whether they show increased HbF has not been reported. We have examined the hematological phenotype, HbF levels, and erythroid BCL11A expression in 3 such patients. Haploinsufficiency of BCL11A induces only partial developmental γ-globin silencing. Of greater interest is that a patient with a downstream deletion exhibits reduced BCL11A expression and increased HbF. Novel erythroid-specific regulatory elements in this region may be required for normal erythroid BCL11A expression, whereas loss of separate elements in the developing brain may explain the neurological phenotype.
•Elevation of HbF in 3 patients heterozygous for distinct 2p15-p16.1 syndrome microdeletions affecting BCL11A.•Identification of novel, putative regulatory elements downstream of BCL11A that govern its expression in erythroid cells.
Abstract
Context
Familial isolated hypoparathyroidism (FIH) is a genetically heterogeneous disorder due to mutations of the calcium-sensing receptor (CASR), glial cells missing-2 (GCM2), guanine ...nucleotide binding protein α11 (GNA11), or parathyroid hormone (PTH) genes. Thus far, only four cases with homozygous and two cases with heterozygous mutations in the PTH gene have been reported.
Objective
To clinically describe an FIH family and identify and characterize the causal gene mutation.
Design
Genomic DNA of the family members was subjected to CASR, GCM2, GNA11, and PTH gene mutational analysis. Functional assays were performed on the variant identified.
Participants
Six subjects of a three-generation FIH family with three affected individuals having severe hypocalcemia and inappropriately low serum PTH.
Results
No mutations were detected in the CASR, GCM2, and GNA11 genes. A heterozygous variant that segregated with the disease was identified in PTH gene exon 2 (c.41T>A; p.M14K). This missense variant, in the hydrophobic core of the signal sequence, was predicted in silico to impair cleavage of preproPTH to proPTH. Functional assays in HEK293 cells demonstrated much greater retention intracellularly but impaired secretion into the medium of the M14K mutant relative to wild type. The addition of the pharmacological chaperone, 4-phenylbutyric acid, led to a reduction of cellular retention and increased accumulation in the cell medium of the M14K mutant.
Conclusions
We report a heterozygous PTH mutation in an FIH family and demonstrate accumulation of the mutant intracellularly and its impaired secretion. An accurate genetic diagnosis in such hypoparathyroid patients is critical for appropriate treatment and genetic counseling.
We report on a heterozygous PTH mutation in an FIH family and demonstrate accumulation of the mutant intracellularly and its impaired secretion.
PDF
