Skeletal pathology in mouse models of Gould syndrome is partially alleviated by genetically reducing TGFß signaling.

Skeletal defects are hallmark features of many extracellular matrix (ECM), and collagen-related disorders. However, a biological function in bone has never been defined for the highly evolutionarily conserved type IV collagen. Collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) form α1α1α2 (IV) heterotrimers that represent a fundamental basement membrane constituent present in every organ of the body, including the skeleton. COL4A1 and COL4A2 mutations cause Gould syndrome, a variable and clinically heterogenous multisystem disorder generally characterized by the presence of cerebrovascular disease with ocular, renal, and muscular manifestations. We have previously identified elevated TGFß signaling as a pathological insult resulting from Col4a1 mutations and demonstrated that reducing TGFß signaling ameliorate ocular and cerebrovascular phenotypes in Col4a1 mutant mouse models of Gould syndrome. In this study, we describe the first characterization of skeletal defects in Col4a1 mutant mice that include a developmental delay in osteogenesis and structural, biomechanical and vascular alterations of mature bones. Using distinct mouse models, we show that allelic heterogeneity influences the presentation of skeletal pathology resulting from Col4a1 mutations. Importantly, we found that TGFß target gene expression is elevated in developing bones from Col4a1 mutant mice and show that genetically reducing TGFß signaling partially ameliorates skeletal manifestations. Collectively, these findings identify a novel and unsuspected role for type IV collagen in bone biology, expand the spectrum of manifestations associated with Gould syndrome to include skeletal abnormalities, and implicate elevated TGFß signaling in skeletal pathogenesis in Col4a1 mutant mice.

Multiorgan manifestations of COL4A1 and COL4A2 variants and proposal for a clinical management protocol.

COL4A1/2 variants are associated with highly variable multiorgan manifestations. Depicting the whole clinical spectrum of COL4A1/2-related manifestations is challenging, and there is no consensus on management and preventative strategies. Based on a systematic review of current evidence on COL4A1/2-related disease, we developed a clinical questionnaire that we administered to 43 individuals from 23 distinct families carrying pathogenic variants. In this cohort, we extended ophthalmological and cardiological examinations to asymptomatic individuals and those with only limited or mild, often nonspecific, clinical signs commonly occurring in the general population (i.e., oligosymptomatic). The most frequent clinical findings emerging from both the literature review and the questionnaire included stroke (203/685, 29.6%), seizures or epilepsy (199/685, 29.0%), intellectual disability or developmental delay (168/685, 24.5%), porencephaly/schizencephaly (168/685, 24.5%), motor impairment (162/685, 23.6%), cataract (124/685, 18.1%), hematuria (63/685, 9.2%), and retinal arterial tortuosity (58/685, 8.5%). In oligosymptomatic and asymptomatic carriers, ophthalmological investigations detected retinal vascular tortuosity (5/13, 38.5%), dysgenesis of the anterior segment (4/13, 30.8%), and cataract (2/13, 15.4%), while cardiological investigations were unremarkable except for mild ascending aortic ectasia in 1/8 (12.5%). Our multimodal approach confirms highly variable penetrance and expressivity in COL4A1/2-related conditions, even at the intrafamilial level with neurological involvement being the most frequent and severe finding in both children and adults. We propose a protocol for prevention and management based on individualized risk estimation and periodic multiorgan evaluations.

COL4A1 gene mutations and perinatal intracranial hemorrhage in neonates: case reports and literature review.

Intracranial hemorrhage may represent a complication of the perinatal period that affects neonatal morbidity and mortality. Very poor data exist about a possible association between mutations of the type IV collagen a1 chain (COL4A1) gene and the development of intracranial hemorrhage, and only sporadic reports focus on intracerebral bleedings already developing in utero or in the neonatal period in infants with such a mutation. This study presents a case series of term neonates affected by intracranial hemorrhage, with no apparent risk factors for the development of this condition, who were carriers of COL4A1 gene variants. This study also provides a review of the most recent scientific literature on this topic, specifically focusing on the available scientific data dealing with the perinatal period.

A distinct subset of urothelial cells with enhanced EMT features promotes chemotherapy resistance and cancer recurrence by increasing COL4A1-ITGB1 mediated angiogenesis.

Drug resistance and tumor recurrence remain clinical challenges in the treatment of urothelial carcinoma (UC). However, the underlying mechanism is not fully understood. Here, we performed single-cell RNA sequencing and identified a subset of urothelial cells with epithelial-mesenchymal transition (EMT) features (EMT-UC), which is significantly correlated with chemotherapy resistance and cancer recurrence. To validate the clinical significance of EMT-UC, we constructed EMT-UC like cells by introducing overexpression of two markers, Zinc Finger E-Box Binding Homeobox 1 (ZEB1) and Desmin (DES), and examined their histological distribution characteristics and malignant phenotypes. EMT-UC like cells were mainly enriched in UC tissues from patients with adverse prognosis and exhibited significantly elevated EMT, migration and gemcitabine tolerance in vitro. However, EMT-UC was not specifically identified from tumorous tissues, certain proportion of them were also identified in adjacent normal tissues. Tumorous EMT-UC highly expressed genes involved in malignant behaviors and exhibited adverse prognosis. Additionally, tumorous EMT-UC was associated with remodeled tumor microenvironment (TME), which exhibited high angiogenic and immunosuppressive potentials compared with the normal counterparts. Furthermore, a specific interaction of COL4A1 and ITGB1 was identified to be highly enriched in tumorous EMT-UC, and in the endothelial component. Targeting the interaction of COL4A1 and ITGB1 with specific antibodies significantly suppressed tumorous angiogenesis and alleviated gemcitabine resistance of UC. Overall, our findings demonstrated that the driven force of chemotherapy resistance and recurrence of UC was EMT-UC mediated COL4A1-ITGB1 interaction, providing a potential target for future UC treatment.

Characterize molecular signatures and establish a prognostic signature of gastric cancer by integrating single-cell RNA sequencing and bulk RNA sequencing.

Gastric cancer is a significant global health concern with complex molecular underpinnings influencing disease progression and patient outcomes. Various molecular drivers were reported, and these studies offered potential avenues for targeted therapies, biomarker discovery, and the development of precision medicine strategies. However, it was posed that the heterogeneity of the disease and the complexity of the molecular interactions are still challenging. By seamlessly integrating data from single-cell RNA sequencing (scRNA-seq) and bulk RNA sequencing (bulk RNA-seq), we embarked on characterizing molecular signatures and establishing a prognostic signature for this complex malignancy. We offered a holistic view of gene expression landscapes in gastric cancer, identified 226 candidate marker genes from 3 different dimensions, and unraveled key players' risk stratification and treatment decision-making. The convergence of molecular insights in gastric cancer progression occurs at multiple biological scales simultaneously. The focal point of this study lies in developing a prognostic model, and we amalgamated four molecular signatures (COL4A1, FKBP10, RNASE1, SNCG) and three clinical parameters using advanced machine-learning techniques. The model showed high predictive accuracy, with the potential to revolutionize patient care by using clinical variables. This will strengthen the reliability of the model and enable personalized therapeutic strategies based on each patient's unique molecular profile. In summary, our research sheds light on the molecular underpinnings of gastric cancer, culminating in a powerful prognostic tool for gastric cancer. With a firm foundation in biological insights and clinical implications, our study paves the way for future validations and underscores the potential of integrated molecular analysis in advancing precision oncology.

COL4A1-related disorder as a mimic of congenital TORCHES infection-Expanding the clinical, neuroimaging and genotype spectrum.

Pseudo-TORCH Syndrome (PTS) encompasses a heterogeneous group of genetic disorders that may clinically and radiologically resemble congenital TORCH infections. These mimickers present with overlapping features manifested as intracranial and systemic abnormalities. Collagen type IV alpha 1 chain (COL4A1)-related diseases, characterized by autosomal dominant inheritance, exhibit a diverse phenotypic spectrum involving cerebrovascular, renal, ophthalmological, cardiac, and muscular abnormalities. Cerebrovascular manifestations range from small-vessel brain disease to large vessel abnormalities, resulting in intracerebral hemorrhage, periventricular leukoencephalopathy, and ventriculomegaly. Additional features include cortical malformations, eye defects, arrhythmias, renal disease, muscular abnormalities, and hematological manifestations. Age of onset varies widely, and phenotypic variability exists even among individuals with the same variant. In this study, we present two cases of COL4A1-related disorder mimicking congenital TORCH infections, highlighting the importance of recognizing genetic mimics in clinical practice.

Identification of seven variants in the col4a1 gene that alter RNA splicing by minigene assay.

Type IV collagen is an integral component of basement membranes. Mutations in COL4A1, one of the key genes encoding Type IV collagen, can result in a variety of diseases. It is clear that a significant proportion of mutations that affect splicing can cause disease directly or contribute to the susceptibility or severity of disease. Here, we analyzed exonic mutations and intronic mutations described in the COL4A1 gene using bioinformatics programs and identified candidate mutations that may alter the normal splicing pattern through a minigene system. We identified seven variants that induce splicing alterations by disrupting normal splice sites, creating new ones, or altering splice regulatory elements. These mutations are predicted to impact protein function. Our results help in the correct molecular characterization of variants in COL4A1 and may help develop more personalized treatment options.

Evaluating neural crest cell migration in a Col4a1 mutant mouse model of ocular anterior segment dysgenesis.

The periocular mesenchyme (POM) is a transient migratory embryonic tissue derived from neural crest cells (NCCs) and paraxial mesoderm that gives rise to most of the structures in front of the eye. Morphogenetic defects of these structures can impair aqueous humor outflow, leading to elevated intraocular pressure and glaucoma. Mutations in collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause Gould syndrome - a multisystem disorder often characterized by variable cerebrovascular, ocular, renal, and neuromuscular manifestations. Approximately one-third of individuals with COL4A1 and COL4A2 mutations have ocular anterior segment dysgenesis (ASD), including congenital glaucoma resulting from abnormalities of POM-derived structures. POM differentiation has been a major focus of ASD research, but the underlying cellular mechanisms are still unclear. Moreover, earlier events including NCC migration and survival defects have been implicated in ASD; however, their roles are not as well understood. Vascular defects are among the most common consequences of COL4A1 and COL4A2 mutations and can influence NCC survival and migration. We therefore hypothesized that NCC migration might be impaired by COL4A1 and COL4A2 mutations. In this study, we used 3D confocal microscopy, gross morphology, and quantitative analyses to test NCC migration in Col4a1 mutant mice. We show that homozygous Col4a1 mutant embryos have severe embryonic growth retardation and lethality, and we identified a potential maternal effect on embryo development. Cerebrovascular defects in heterozygous Col4a1 mutant embryos were present as early as E9.0, showing abnormal cerebral vasculature plexus remodeling compared to controls. We detected abnormal NCC migration within the diencephalic stream and the POM in heterozygous Col4a1 mutants whereby mutant NCCs formed smaller diencephalic migratory streams and POMs. In these settings, migratory NCCs within the diencephalic stream and POM localize farther away from the developing vasculature. Our results show for the first time that Col4a1 mutations lead to cranial NCCs migratory defects in the context of early onset defective angiogenesis without affecting cell numbers, possibly impacting the relation between NCCs and the blood vessels during ASD development.

Missense Variants in COL4A1/2 Are Associated with Cerebral Aneurysms: A Case Report and Literature Review.

BACKGROUND: Although cerebral aneurysm (CA) is a defining complication of COL4A1/2-related vasculopathy, the specific factors influencing its onset remain uncertain. This study aimed to identify and analyze these factors. METHODS: We described a family presenting with a novel variant of the COL4A1 gene complicated with CA. Concurrently, an exhaustive review of previously documented patients with COL4A1/2-related vasculopathy was conducted by sourcing data from PubMed, Web of Science, Google Scholar, and Ichushi databases. We compared the variant types and locations between patients with CA (positive group) and those without CA (negative group). RESULTS: This study included 53 COL4A1/2 variants from 76 patients. Except for one start codon variant, all the identified variants in CA were missense variants. Otherwise, CA was not associated with other clinical manifestations, such as small-vessel disease or other large-vessel abnormalities. A higher frequency of missense variants (95.5% vs. 58.1%, p = 0.0035) was identified in the CA-positive group. CONCLUSIONS: CA development appears to necessitate qualitative alterations in COL4A1/2, and the underlying mechanism seems independent of small-vessel disease or other large-vessel anomalies. Our findings suggest that a meticulous evaluation of CA is necessary when missense variants in COL4A1/2 are identified.

Collagen type IV alpha 1 chain (COL4A1) expression in the developing human lung.

BACKGROUND: Collagen type IV alpha 1 chain (COL4A1) in the basement membrane is an important component during lung development, as suggested from animal models where COL4A1 has been shown to regulate alveolarization and angiogenesis. Less is known about its role in human lung development. Our aim was to study COL4A1 expression in preterm infants with different lung maturational and clinical features. METHODS: COL4A1 expression in 115 lung samples from newborn infants (21-41 weeks' gestational age; 0-228 days' postnatal age [PNA]) was studied by immunohistochemistry combined with digital image analysis. Cluster analysis was performed to find subgroups according to immunohistologic and clinical data. RESULTS: Patients were automatically categorized into 4 Groups depending on their COL4A1 expression. Expression of COL4A1 was mainly extracellular in Group 1, low in Group 2, intracellular in Group 3, and both extra- and intracellular in Group 4. Intracellular/extracellular ratio of COL4A1 expression related to PNA showed a distinctive postnatal maturational pattern on days 1-7, where intracellular expression of COL4A1 was overrepresented in extremely preterm infants. CONCLUSIONS: COL4A1 expression seems to be highly dynamic during the postnatal life due to a possible rapid remodeling of the basement membrane. Intracellular accumulation of COL4A1 in the lungs of extremely premature infants occurs more frequently between 1 and 7 postnatal days than during the first 24 hours. In view of the lung arrest described in extremely preterm infants, the pathological and/or developmental role of postnatally increased intracellular COL4A1 as marker for basement membrane turnover, needs to be further investigated.

Potential risks associated with laparoscopic gastrostomy in patients with the COL4A1 variant: Two case reports.

The COL4A1 (collagen Type 4 alpha1) pathogenic variant is associated with porencephaly and schizencephaly and accounts for approximately 20% of these patients. This gene variant leads to systemic microvasculopathy, which manifests as brain, ocular, renal, and muscular disorders. However, only a few patients with surgical interventions have been reported and the potential surgical risks are unknown. Here, we present the cases of two female patients between 7 and 8 years of age who were diagnosed with the COL4A1 variant and underwent laparoscopy-assisted percutaneous endoscopic gastrostomy (LAPEG) for oral dysphagia. Their primary brain lesions were caused by porencephaly and paralysis, which are caused by multiple cerebral hemorrhages and infarctions, and both patients had refractory epileptic complications. Although LAPEG was successfully performed in both patients without any intraoperative complications, one patient developed alveolar hemorrhage postoperatively and required mechanical ventilation. Thus, careful perioperative management of patients with the COL4A1 variant is important.

A Novel, Possibly Pathogenic, COL4A1 Gene Variant (c.3698G>A) in a Family With Childhood Epilepsy and Leukoencephalopathy.

This case report explores the clinical presentation and genetic findings of a 44-year-old male with a history of pediatric epilepsy. The patient's daughter, recently diagnosed with autism, underwent genetic testing, revealing a variant of uncertain significance (VUS) in the type IV collagen alpha 1 (COL4A1) gene. The male patient reported a spectrum of neurological symptoms, including chronic migraines, exertional weakness, and sensory disturbances. Detailed neurological examination findings were within normal limits, but a brain MRI unveiled confluent deep white matter T2/fluid-attenuated inversion recovery (FLAIR) signal abnormalities with basal ganglia involvement. Genetic testing identified a novel COL4A1 gene variant, c.3698G>A (p.Gly1233Glu), in the patient, which was also carried by his daughter. The nature and clinical implications of this VUS in the context of the family's clinical history are discussed in this case report, emphasizing the potential significance of this genetic variant in understanding the etiology of the patient's neurologic symptoms. Further research and correlation with clinical findings are needed to elucidate whether this is a pathogenic variant.

'Raisin bread sign' feature of pontine autosomal dominant microangiopathy and leukoencephalopathy.

Pontine autosomal dominant microangiopathy and leukoencephalopathy is one of hereditary cerebral small vessel diseases caused by pathogenic variants in COL4A1 3'UTR and characterized by multiple small infarctions in the pons. We attempted to establish radiological features of this disease. We performed whole exome sequencing and Sanger sequencing in one family with undetermined familial small vessel disease, followed by clinicoradiological assessment and a postmortem examination. We subsequently investigated clinicoradiological features of patients in a juvenile cerebral vessel disease cohort and searched for radiological features similar to those found in the aforementioned family. Sanger sequencing was performed in selected cohort patients in order to detect variants in the same gene. An identical variant in the COL4A1 3'UTR was observed in two patients with familial small vessel disease and the two selected patients, thereby confirming the pontine autosomal dominant microangiopathy and leukoencephalopathy diagnosis. Furthermore, postmortem examination showed that the distribution of thickened media tunica and hyalinized vessels was different from that in lacunar infarctions. The appearance of characteristic multiple oval small infarctions in the pons, which resemble raisin bread, enable us to make a diagnosis of pontine autosomal dominant microangiopathy and leukoencephalopathy. This feature, for which we coined the name 'raisin bread sign', was also correlated to the pathological changes.

A novel human iPSC model of COL4A1/A2 small vessel disease unveils a key pathogenic role of matrix metalloproteinases.

Cerebral small vessel disease (SVD) affects the small vessels in the brain and is a leading cause of stroke and dementia. Emerging evidence supports a role of the extracellular matrix (ECM), at the interface between blood and brain, in the progression of SVD pathology, but this remains poorly characterized. To address ECM role in SVD, we developed a co-culture model of mural and endothelial cells using human induced pluripotent stem cells from patients with COL4A1/A2 SVD-related mutations. This model revealed that these mutations induce apoptosis, migration defects, ECM remodeling, and transcriptome changes in mural cells. Importantly, these mural cell defects exert a detrimental effect on endothelial cell tight junctions through paracrine actions. COL4A1/A2 models also express high levels of matrix metalloproteinases (MMPs), and inhibiting MMP activity partially rescues the ECM abnormalities and mural cell phenotypic changes. These data provide a basis for targeting MMP as a therapeutic opportunity in SVD.

Identification and Validation of Signature Genes and Potential Therapy Targets of Inflammatory Bowel Disease and Periodontitis.

Background: Inflammatory bowel disease (IBD) and periodontitis (PD) are correlated, although the pathogenic mechanism behind their correlation has not been clarified. This study aims to explore the common signature genes and potential therapeutic targets of IBD and PD using transcriptomic analysis. Methods: The GEO database was used to download datasets of IBD and PD, and differential expression analysis was used to identify DEGs. We then conducted GO and KEGG enrichment analyses of the shared genes. Next, we applied 4 machine learning (ML) algorithms (GLM, RF, GBM, and SVM) to select the best prediction model for diagnosing the disease and obtained the hub genes of IBD and PD. The diagnostic value of the signature genes was verified by a validation set and qRT‒PCR experiments. Subsequently, immune cell infiltration in IBD samples and PD samples was analyzed by ssGSEA. Finally, we investigated and validated the response of hub genes to infliximab therapy. Results: We identified 43 upregulated genes as shared genes by intersecting the DEGs of IBD and PD. Functional enrichment analysis suggested that the shared genes were closely associated with immunity and inflammation. The ML algorithm and qRT‒PCR results indicated that IGKC and COL4A1 were the hub genes with the most diagnostic value for IBD and PD. Subsequently, through immune infiltration analysis, CD4 T cells, NK cells and neutrophils were identified to play crucial roles in the pathogenesis of IBD and PD. Finally, through in vivo and in vitro experiments, we found that IGKC and COL4A1 were significantly downregulated during the treatment of patients with IBD using infliximab. Conclusion: We investigated the potential association between IBD and PD using transcriptomic analysis. The IGKC and COL4A1 genes were identified as characteristic genes and novel intervention targets for these two diseases. Infliximab may be used to treat or prevent IBD and PD.

Case report: Recurrent pontine stroke and leukoencephalopathy in a patient with de novo mutation in COL4A1.

This report presents a case of pontine autosomal dominant microangiopathy with leukoencephalopathy (PADMAL) in a 35 year-old male patient. The patient exhibited a consistent history of recurrent ischemic strokes, concentrated primarily in the pons region, accompanied by concurrent manifestations of leukoencephalopathy and microbleeds. Genetic evaluation revealed a heterozygous missense mutation consistent with c.3431C>G, p. Thr1144Arg substitution within exon 40 of the COL4A1 gene. This mutation was also identified in the patient's mother, affirming an autosomal dominant inheritance model. Our findings serve as testament to the potential role of mutation in the exon 40 of COL4A1 in the pathogenesis and progression of PADMAL, contributing to ongoing efforts aimed at better understanding the genetic basis of this debilitating disorder.

Spectrum of Fetal Intraparenchymal Hemorrhage in COL4A1/A2-Related Disorders.

BACKGROUND: COL4A1/A2 variants affecting the alpha 1 and 2 chains of type IV collagen are increasingly recognized as a cause of fetal and neonatal intracranial hemorrhage, porencephaly, and schizencephaly. Fetal magnetic resonance imaging (MRI) findings in COL4A1/A2-related disorders are not well characterized. METHODS: This is a retrospective case series of fetal MRI findings in eight patients with intraparenchymal hemorrhage (IPH) and COL4A1/A2 variants, five of whom have postnatal imaging and clinical follow-up. RESULTS: IPH was multifocal and bilateral in four of eight patients. IPH involved the frontal lobes in all cases and basal ganglia in six of eight. The median maximum diameter of IPH was 16 mm (range 6 to 65 mm). All patients had ventriculomegaly, and four of eight had intraventricular hemorrhage. Prenatal IPH size correlated clinically with motor outcomes, and none had clinically symptomatic recurrent hemorrhage. CONCLUSION: COL4A1/A2 variants can present with a spectrum of IPH prenatally, including small and/or unifocal IPH, as well as multifocal and bilateral IPH, involving the frontal lobes and basal ganglia. Given the wide spectrum of IPH severity seen on fetal brain MRI, genetic testing for COL4A1/A2 variants should be considered in all cases of fetal IPH.

Genotypic Analysis of COL4A1 Gene in Diabetic Nephropathy and Type 2 Diabetes Mellitus Patients: A Comparative Genetic Study.

Diabetic nephropathy (DN) is specified by microalbuminuria, glomerular lesions, and renal fibrosis leading to end-stage renal disease. The pathophysiology of DN is multifactorial as a result of gene-environment interaction. Clinical studies suggested that gene mutations affect various pathways involved in DN, including extracellular matrix (ECM). During chronic hyperglycemia, collagen type-4-mediated ECM overproduction occurs, leading to renal fibrosis and DN development. In this study, COL4A1 gene variant rs605143 (G/A) was analyzed in diabetes and DN patients from the study population. We genotyped 386 study subjects, comprising 120 type 2 diabetes mellitus (T2DM) patients, 120 DN, and 146 healthy controls. All study subjects were analyzed for biochemical assays by commercially available kits and genotypic analysis by polymerase chain reaction-restriction fragment length polymorphism and confirmed by Sanger sequencing. Statistical analyses were done using SPSS and GraphPad. Anthroclinicopathological parameters showed a significant association between T2DM and DN. Genotype AA of COL4A1 gene variant rs605143 (G/A) showed a significant association with T2DM and DN compared with controls with 5.87- and 8.01-folds risk, respectively. Mutant allele A also significantly associated with T2DM and DN independently compared with healthy controls with 2.29- and 2.81-time risk in the study population. This study's findings suggested that COL4A1 gene variant rs605143 (G/A) can be used as predictive biomarkers for T2DM and DN independently. However, this gene variant needs to be analyzed in a large sample to explore the shared genetic association between T2DM and DN.

PI3K block restores age-dependent neurovascular coupling defects associated with cerebral small vessel disease.

Neurovascular coupling (NVC), a vital physiological process that rapidly and precisely directs localized blood flow to the most active regions of the brain, is accomplished in part by the vast network of cerebral capillaries acting as a sensory web capable of detecting increases in neuronal activity and orchestrating the dilation of upstream parenchymal arterioles. Here, we report a Col4a1 mutant mouse model of cerebral small vessel disease (cSVD) with age-dependent defects in capillary-to-arteriole dilation, functional hyperemia in the brain, and memory. The fundamental defect in aged mutant animals was the depletion of the minor membrane phospholipid phosphatidylinositol 4,5 bisphosphate (PIP2) in brain capillary endothelial cells, leading to the loss of inwardly rectifying K+ (Kir2.1) channel activity. Blocking phosphatidylinositol-3-kinase (PI3K), an enzyme that diminishes the bioavailability of PIP2 by converting it to phosphatidylinositol (3, 4, 5)-trisphosphate (PIP3), restored Kir2.1 channel activity, capillary-to-arteriole dilation, and functional hyperemia. In longitudinal studies, chronic PI3K inhibition also improved the memory function of aged Col4a1 mutant mice. Our data suggest that PI3K inhibition is a viable therapeutic strategy for treating defective NVC and cognitive impairment associated with cSVD.

High Prevalence of Collagenopathies in Preterm- and Term-Born Children With Periventricular Venous Hemorrhagic Infarction.

INTRODUCTION: The aim of this study was to evaluate genetic risk factors in term-born children with antenatal periventricular hemorrhagic infarction (PVHI), presumed antenatal periventricular venous infarction and periventricular hemorrhagic infarction in preterm neonates. METHODS: Genetic analysis and magnetic resonance imaging were performed in 85 children: term-born children (≥36 gestational weeks) with antenatal periventricular hemorrhagic infarction (n = 6) or presumed antenatal (n = 40) periventricular venous infarction and preterm children (<36 gestational weeks) with periventricular hemorrhagic infarction (n = 39). Genetic testing was performed using exome or large gene panel (n = 6700 genes) sequencing. RESULTS: Pathogenic variants associated with stroke were found in 11 of 85 (12.9%) children with periventricular hemorrhagic infarction/periventricular venous infarction. Among the pathogenic variants, COL4A1/A2 and COL5A1 variants were found in 7 of 11 (63%) children. Additionally, 2 children had pathogenic variants associated with coagulopathy, whereas 2 other children had other variants associated with stroke. Children with collagenopathies had significantly more often bilateral multifocal stroke with severe white matter loss and diffuse hyperintensities in the white matter, moderate to severe hydrocephalus, moderate to severe decrease in size of the ipsilesional basal ganglia and thalamus compared to children with periventricular hemorrhagic infarction/periventricular venous infarction without genetic changes in the studied genes (P ≤ .01). Severe motor deficit and epilepsy developed more often in children with collagenopathies compared to children without genetic variants (P = .0013, odds ratio [OR] = 233, 95% confidence interval [CI]: 2.8-531; and P = .025, OR = 7.3, 95% CI: 1.3-41, respectively). CONCLUSIONS: Children with periventricular hemorrhagic infarction/periventricular venous infarction have high prevalence of pathogenic variants in collagene genes (COL4A1/A2 and COL5A1). Genetic testing should be considered for all children with periventricular hemorrhagic infarction/periventricular venous infarction; COL4A1/A2 and COL5A1/A2 genes should be investigated first.