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Background: Mucopolysaccharidoses (MPS) are rare lysosomal storage disorders caused by deficiencies in glycosaminoglycan (GAG)-degrading enzymes, leading to progressive multisystem involvement.

Methods: We evaluated two unrelated consanguineous Pakistani families, each with three individuals showing features consistent with MPS. Affected individuals in Family 1 presented with developmental regression, severe cognitive impairment, behavioral abnormalities and facial dysmorphisms. The affected individuals in Family 2 showed classical skeletal dysplasia consistent with Morquio syndrome. Whole-exome sequencing (WES), segregation analysis, and in silico protein modeling were performed to identify and characterize pathogenic gene variants.

Results: Analysis of WES data revealed a homozygous missense variant in the SGSH gene [c.548G>A (p.Cys183Tyr)] in the three cases of Family 1 and a homozygous splice-site variant in the GALNS gene (c.423-1G>A) in the cases of Family 2. The SGSH variant, located within the sulfatase catalytic domain and classified as likely pathogenic (ACMG), is consistent with the Sanfilippo A phenotype and represents the first clinical characterization of this allele. Regarding Family 2, we identified the GALNS mutation as a recurrent pathogenic founder allele previously reported in individuals of South Asian descent. Structural modeling of SGSH p.Cys183Tyr predicted disruption of a conserved cysteine residue and altered protein stability, likely supporting its deleterious effect.

Conclusions: This study expands the spectrum of MPS-associated variants in Pakistan. The findings underscore the importance of genomic diagnostics for enabling early detection, accurate classification, and genetic counseling in populations with high consanguinity.

Charcot-Marie-Tooth (CMT) is a group of inherited neuromuscular disorders with diverse clinical features such as muscle weakness and atrophy of the distal regions, foot deformities, sensory loss and decreased or absent reflexes. With the diverse inheritance patterns including dominant, recessive, and X-linked, it exhibits significant genetic heterogeneity often overlapping with other neurological disorders. Whole exome sequencing (WES) has emerged as favorable diagnostic tool for such challenging disease entities. We recruited five Pakistani families that consisted of 14 affected individuals exhibiting representative symptoms of CMT such as severe muscle weakness of the lower limbs, muscles atrophy, claw hands and feet deformities. WES data analysis revealed two novel and two already reported homozygous missense variants in GDAP1 (NM_018972) c.1A > G (p. Met1Val), c.683A > G (p. Glu228Gly), c.734C > T (p. Thr245Ile) and c.811G > A (p. Gly271Arg) in families A-D, respectively. While a novel homozygous SBF2 variant c.2746G > C, p. (Gly916Arg) was identified in family E. Sanger sequencing confirm the segregation of all candidate variants in their respective pedigrees. Moreover, molecular modeling supports the destabilizing effect of these variants on final protein product of both GDAP1 and SBF2 by inducing modifications in overall conformation of the protein. The present study expands the mutation spectrum of the GDAP1 and SBF2 genes, with possible implications for improved understanding of disease pathophysiology. Furthermore, the current study highlights the importance of NGS, particularly WES, in achieving rapid and precise molecular genetic diagnosis for clinical purposes, especially in neuromuscular disorders of heterogeneous nature.

Plasma proteomic profiling of 92 individuals with Post-Acute Sequelae of SARS-CoV-2 infection (PASC), assessed a mean of 34 months after acute infection, revealed a distinct inflammatory signature. Using proximity extension assay technology, 358 proteins were quantified, identifying 26 differentially expressed proteins (DEPs) in PASC: 23 upregulated and 3 downregulated. The most upregulated proteins were Oncostatin M (OSM) and IL-1 receptor antagonist (IL1RN). Additional increases were observed in IL-6, IL-12B, IL-2, CCL22, CSF3, CSF1, and HLA-DRA, as well as proteins involved in tissue remodeling and angiogenesis such as ANGPTL2 and TGFA. Random forest analysis confirmed IL1RN, OSM, ANGPTL2, HLA-DRA, and CLEC4A as strong discriminators between patients and controls. Gene set enrichment analysis demonstrated activation of multiple immune pathways, including Inflammatory Response, TNF-alpha/NF-kappa B signaling, IL-6/JAK/STAT3, IL-2/STAT5, and Allograft Rejection, indicating persistent activation of innate and adaptive immunity. STRING network analysis highlighted a tightly connected cytokine-driven inflammatory module. Plasma spike protein levels did not differ between patients and controls, suggesting that PASC-related inflammation may persist independently of ongoing viral replication. Overall, the findings indicate a consistent low-grade inflammatory state in PASC without evidence for distinct biological subtypes.

Dravet syndrome (DS) is a severe pediatric epilepsy primarily caused by de novo mutation in the SCN1A gene encoding the alpha subunit of the voltage-gated sodium channel. While early in vivo studies linked DS pathology to GABAergic disinhibition, recent studies report altered sodium currents in both inhibitory and excitatory neurons. In vitro models containing both neuronal subtypes may offer deeper insights into functionality of neuronal networks. This study examined the effects of two different SCN1A pathogenic variants on the functional phenotype of human induced pluripotent stem cell-derived enriched GABAergic cultures and heterogeneous GABA-and glutamatergic cultures using microelectrode arrays. We observed functional differences evident as increased network bursts in one DS patient line compared to controls and to another DS patient line in GABAergic and heterogenous cultures. Importantly, heterogeneous cultures revealed lower spiking and bursting frequency in both DS patient lines. Principal component analysis confirmed distinct clustering of the functional profiles of the DS patient and control networks in heterogeneous cultures. The magnitude of the altered functional activity reflected the clinical severity of the disease. Thus, functional alterations caused by SCN1A variants are apparent in heterogenous cultures indicating their competence for characterizing disease phenotypes in DS.

Background: Post-acute sequelae of SARS-CoV-2 infection (PASC), also known as post-COVID-19 condition (here abbreviated as post-COVID) is an escalating global health issue. The aim of our study was to investigate the mechanisms and clinical manifestations of post-COVID following a mild SARS-CoV-2 infection.

Methods: We analyzed the gene expression profile in PBMCs from 60 middle-aged post-COVID patients and 50 age-matched controls at a median time of 28 months following a mild SARS-CoV-2 infection. The clinical assessments included intensity of post-COVID symptoms, physical and mental fatigue, depression and anxiety. Sixty-seven participants performed a mild exertion ergometer test with assessment of lactate concentrations. Transcriptome analysis was performed on mRNA selected by poly-A enrichment and SARS-CoV-2 RNA fragments were analyzed using the ARTIC protocol.

Results: We identified 463 differentially expressed transcripts in PBMCs, of which 324 were upregulated and 129 downregulated in post-COVID patients. Upregulated genes in post-COVID individuals were enriched for processes involving JAK-STAT signaling, negative regulation of ubiquitination, IL9 signaling, and negative regulation of viral process, suggesting chronic inflammation. Downregulated genes were enriched for processes involving mitochondrial ATP synthesis, and oxidative phosphorylation, suggesting mitochondrial dysfunction. No SARS-CoV-2 gene fragments were detected in PBMCs of patients with post-COVID and no IFN genes were found differentially expressed in post-COVID patients. Post-COVID was associated with elevated lactate levels in blood, both at rest and after a short recovery phase following exertion, suggesting increased anaerobic activity in skeletal muscles. We did not find differences in the transcriptional profiles or clinical manifestations when comparing patients who contracted the infection from early SARS-CoV-2 variants with those who contracted the infection during the period when the Omicron variant was prevalent.

Conclusions: Our findings highlight molecular changes compatible with a persistent immune response in PBMCs of post-COVID subjects at a median follow-up of 28 months after a mild infection, supporting the hypothesis that post-COVID is a chronic inflammatory condition. The upregulation of JAK/STAT signaling suggests a potential therapeutic target in post-COVID.

Cerebral cavernous malformation (CCM) is a neurovascular disease distinguished by clusters of leaky, mulberry-like blood vessels. KRIT1 bi-allelic loss-of-function mutations in endothelial cells are known to trigger brain cavernomas; however, human preclinical models are needed to unveil the importance of germline KRIT1 heterozygous mutations in CCM pathogenesis. We generated three induced pluripotent stem cells (iPSCs) from patients with CCM with hereditary KRIT1 heterozygous mutations. Patient-derived vascularized organoids exhibited intricate and abnormal vascular structures with cavernoma-like morphology, and iPSC-derived endothelial cells displayed phenotypic abnormalities at the junctional and transcriptional levels. Upon injection into brain explants, CCM endothelial cells integrated into the normal vasculature and created vascular anomalies. Lastly, transcriptional analysis showed that the endothelial progenitor marker paternally expressed gene 3 (PEG3) was highly expressed in iPSC-derived CCM endothelial cells, and this was further confirmed in familial and sporadic cavernoma biopsies. Overall, our study sheds light on the molecular consequence of KRIT1 heterozygous mutations in endothelial cells and the potential implications in cavernoma pathogenesis.

Dravet syndrome (DS) is a devastating early-onset refractory epilepsy syndrome caused by variants in the SCN1A gene. A disturbed GABAergic interneuron function is implicated in the progression to DS but the underlying developmental and pathophysiological mechanisms remain elusive, in particularly at the chromatin level. Induced pluripotent stem cells (iPSCs) derived from DS cases and healthy donors were used to model disease-associated epigenetic abnormalities of GABAergic development. Chromatin accessibility was assessed at multiple time points (Day 0, Day 19, Day 35, and Day 65) of GABAergic differentiation. Additionally, the effects of the commonly used anti-seizure drug valproic acid (VPA) on chromatin accessibility were elucidated in GABAergic cells. The distinct dynamics in the chromatin profile of DS iPSC predicted accelerated early GABAergic development, evident at D19, and diverged further from the pattern in control iPSC with continued differentiation, indicating a disrupted GABAergic maturation. Exposure to VPA at D65 reshaped the chromatin landscape at a variable extent in different iPSC-lines and rescued the observed dysfunctional development of some DS iPSC-GABA. The comprehensive investigation on the chromatin landscape of GABAergic differentiation in DS-patient iPSC offers valuable insights into the epigenetic dysregulations associated with interneuronal dysfunction in DS. Moreover, the detailed analysis of the chromatin changes induced by VPA in iPSC-GABA holds the potential to improve the development of personalized and targeted anti-epileptic therapies.

The transcription factor ZEB2 is essential for early embryonic development. Using CRISPR/Cas9, we generated a ZEB2 deficient human iPSC cell line (KICRi002A-4), carrying a homozygous 790 bp deletion in ZEB2 that involves part of exon 5, intron 5 and part of exon 6. The deletion leads to markedly reduced levels of a truncated ZEB2 transcript. No ZEB2 protein was detected by immunopreciptation. The iPSC line expressed pluripotency markers and showed a capacity to differentiate into three germ layers in vitro. . Assessment of genomic integrity revealed a normal karyotype without detectable OFF-target editing. The iPSC line KICRi002A-4 thus a valuable resource to study the role of ZEB2 for the commitment and differentiation of various human cell lineages.

Background: Microcephaly with early-onset seizures (MCSZ) is a neurodevelopmental disorder caused by pathogenic variants in the DNA strand break repair protein, polynucleotide kinase 3 '-phosphatase (PNKP).

Methods: We have used whole genome sequencing and Sanger sequencing to identify disease-causing variants, followed by a minigene assay, Western blotting, alkaline comet assay, gamma H2AX, and ADP-ribose immunofluorescence.

Results: Here, we describe a patient with compound heterozygous variants in PNKP, including a missense variant in the DNA phosphatase domain (T323M) and a novel splice acceptor site variant within the DNA kinase domain that we show leads to exon skipping. We show that primary fibroblasts derived from the patient exhibit greatly reduced levels of PNKP protein and reduced rates of DNA single-strand break repair, confirming that the mutated PNKP alleles are dysfunctional.

Conclusion: The data presented show that the detected compound heterozygous variants result in reduced levels of PNKP protein, which affect the repair of both oxidative and TOP1-induced single-strand breaks, and most likely causes MCSZ in this patient.

Methods One severely affected individual underwent thorough investigation with neurophysiological and blood pressure (BP) measurements, including direct recording of baroreflex-governed sympathetic nerve signalling and induction of BP rise with phenylephrine. Family members underwent parts of the examination. Genetic analysis using exome sequencing was performed.

Results Marked postural hypotension with greatly reduced cardiac preload was observed, but without signs of autonomic nervous system dysfunction: sympathetic nerve signalling was normal, as were catecholamine levels, and phenylephrine stimulation revealed a normal increase in BP. The results of the genetic analysis using exome sequencing comprising all known genes associated with the regulation of BP and catecholamine metabolism were normal.

Conclusion The combined findings suggest an autosomal dominant form of early-onset orthostatic hypotension with variable clinical expression and without any additional autonomic dysfunction. It is possible that further investigation will reveal an as yet undescribed entity of orthostatic hypotension transmitted as an autosomal dominant trait.