Novel patients with NHLRC2 variants expand the phenotypic spectrum of FINCA disease.

Purpose: FINCA disease (Fibrosis, Neurodegeneration and Cerebral Angiomatosis, OMIM 618278) is an infantile-onset neurodevelopmental and multiorgan disease. Since our initial report in 2018, additional patients have been described. FINCA is the first human disease caused by recessive variants in the highly conserved NHLRC2 gene. Our previous studies have shown that Nhlrc2-null mouse embryos die during gastrulation, indicating the essential role of the protein in embryonic development. Defect in NHLRC2 leads to cerebral neurodegeneration and severe pulmonary, hepatic and cardiac fibrosis. Despite having a structure suggestive of an enzymatic role and the clinical importance of NHLRC2 in multiple organs, the specific physiological role of the protein is unknown. Methods: The clinical histories of five novel FINCA patients diagnosed with whole exome sequencing were reviewed. Segregation analysis of the biallelic, potentially pathogenic NHLRC2 variants was performed using Sanger sequencing. Studies on neuropathology and NHLRC2 expression in different brain regions were performed on autopsy samples of three previously described deceased FINCA patients. Results: One patient was homozygous for the pathogenic variant c.442G > T, while the other four were compound heterozygous for this variant and two other pathogenic NHLRC2 gene variants. All five patients presented with multiorgan dysfunction with neurodevelopmental delay, recurrent infections and macrocytic anemia as key features. Interstitial lung disease was pronounced in infancy but often stabilized. Autopsy samples revealed widespread, albeit at a lower intensity than the control, NHLRC2 expression in the brain. Conclusion: This report expands on the characteristic clinical features of FINCA disease. Presentation is typically in infancy, and although patients can live to late adulthood, the key clinical and histopathological features are fibrosis, infection susceptibility/immunodeficiency/intellectual disability, neurodevelopmental disorder/neurodegeneration and chronic anemia/cerebral angiomatosis (hence the acronym FINCA) that enable an early diagnosis confirmed by genetic investigations.

Impact of constitutional TET2 haploinsufficiency on molecular and clinical phenotype in humans.

Clonal hematopoiesis driven by somatic heterozygous TET2 loss is linked to malignant degeneration via consequent aberrant DNA methylation, and possibly to cardiovascular disease via increased cytokine and chemokine expression as reported in mice. Here, we discover a germline TET2 mutation in a lymphoma family. We observe neither unusual predisposition to atherosclerosis nor abnormal pro-inflammatory cytokine or chemokine expression. The latter finding is confirmed in cells from three additional unrelated TET2 germline mutation carriers. The TET2 defect elevates blood DNA methylation levels, especially at active enhancers and cell-type specific regulatory regions with binding sequences of master transcription factors involved in hematopoiesis. The regions display reduced methylation relative to all open chromatin regions in four DNMT3A germline mutation carriers, potentially due to TET2-mediated oxidation. Our findings provide insight into the interplay between epigenetic modulators and transcription factor activity in hematological neoplasia, but do not confirm the putative role of TET2 in atherosclerosis.

Impact of Young Age on the Presentation of Saccular Intracranial Aneurysms: Population-Based Analysis of 4082 Patients.

BACKGROUND: Formation and rupture of saccular intracranial aneurysms (sIAs) may have different pathobiologies in patients with younger age at first diagnosis of sIA disease. OBJECTIVE: To study the phenotype of sIA disease and formation of new (de novo) sIAs in patients below 40 yr. METHODS: A population-based cohort study was conducted in 613 young (<40 yr) sIA patients with first diagnosis between 1980 and 2014 and total angiographic follow-up of 3768 yr. RESULTS: Of the 613 sIA patients <40 yr, 508 had aneurysmal subarachnoid hemorrhage (sIA-SAH) and 105 unruptured sIA(s) at first sIA diagnosis. Hypertension was 2 times less common among <40 than >40-yr-old patients (unruptured and ruptured). Smoking was very prevalent in <40-yr-old patients (33% in SAH, 68% unruptured). SAH patients <40 yr more often had family history of sIA, and lower PHASES scores (age omitted, P < .001). Ruptured sIAs were small (<7 mm) in 33% of 39 to 30 yr patients, in 44% of 29 to 20 yr patients, and 57% of <19 yr patients. Their shape was irregular in 90%, 94%, and 95%, respectively. Smoking history (hazard ratio [HR] 2.8, 95% confidence interval [CI] 1.2-7.0), family history for sIAs (HR 3.1, 95% CI 1.3-7.7), and age at presentation (HR .91 per year, 95% CI .85-.98) were risk factors for de novo sIA formation, diagnosed in 4% even after 20 yr (median 11.8 yr). CONCLUSION: Smoking and family history are risk factors for sIA formation and aneurysmal SAH at young age. Young aneurysmal SAH patients had lower PHASES scores and often rupture from a small sIA, suggesting need for more aggressive management.

Protective Low-Frequency Variants for Preeclampsia in the Fms Related Tyrosine Kinase 1 Gene in the Finnish Population.

Preeclampsia is a common pregnancy-specific vascular disorder characterized by new-onset hypertension and proteinuria during the second half of pregnancy. Predisposition to preeclampsia is in part heritable. It is associated with an increased risk of cardiovascular disease later in life. We have sequenced 124 candidate genes implicated in preeclampsia to pinpoint genetic variants contributing to predisposition to or protection from preeclampsia. First, targeted exomic sequencing was performed in 500 preeclamptic women and 190 controls from the FINNPEC cohort (Finnish Genetics of Preeclampsia Consortium). Then 122 women with a history of preeclampsia and 1905 parous women with no such history from the National FINRISK Study (a large Finnish population survey on risk factors of chronic, noncommunicable diseases) were included in the analyses. We tested 146 rare and low-frequency variants and found an excess (observed 13 versus expected 7.3) nominally associated with preeclampsia (P<0.05). The most significantly associated sequence variants were protective variants rs35832528 (E982A; P=2.49E-4; odds ratio=0.387) and rs141440705 (R54S; P=0.003; odds ratio=0.442) in Fms related tyrosine kinase 1. These variants are enriched in the Finnish population with minor allele frequencies 0.026 and 0.017, respectively. They may also be associated with a lower risk of heart failure in 11 257 FINRISK women. This study provides the first evidence of maternal protective genetic variants in preeclampsia.

De Novo Truncating Variants in ASXL2 Are Associated with a Unique and Recognizable Clinical Phenotype.

The ASXL genes (ASXL1, ASXL2, and ASXL3) participate in body patterning during embryogenesis and encode proteins involved in epigenetic regulation and assembly of transcription factors to specific genomic loci. Germline de novo truncating variants in ASXL1 and ASXL3 have been respectively implicated in causing Bohring-Opitz and Bainbridge-Ropers syndromes, which result in overlapping features of severe intellectual disability and dysmorphic features. ASXL2 has not yet been associated with a human Mendelian disorder. In this study, we performed whole-exome sequencing in six unrelated probands with developmental delay, macrocephaly, and dysmorphic features. All six had de novo truncating variants in ASXL2. A careful review enabled the recognition of a specific phenotype consisting of macrocephaly, prominent eyes, arched eyebrows, hypertelorism, a glabellar nevus flammeus, neonatal feeding difficulties, hypotonia, and developmental disabilities. Although overlapping features with Bohring-Opitz and Bainbridge-Ropers syndromes exist, features that distinguish the ASXL2-associated condition from ASXL1- and ASXL3-related disorders are macrocephaly, absence of growth retardation, and more variability in the degree of intellectual disabilities. We were also able to demonstrate with mRNA studies that these variants are likely to exert a dominant-negative effect, given that both alleles are expressed in blood and the mutated ASXL2 transcripts escape nonsense-mediated decay. In conclusion, de novo truncating variants in ASXL2 underlie a neurodevelopmental syndrome with a clinically recognizable phenotype. This report expands the germline disorders that are linked to the ASXL genes.

High Risk of Dementia in Ventricular Enlargement with Normal Pressure Hydrocephalus Related Symptoms1.

BACKGROUND: Differential diagnosis of ventricular enlargement with normal pressure hydrocephalus (NPH) related symptoms is challenging. Patients with enlarged ventricles often manifest cognitive deterioration but their long-term outcome is not well known. OBJECTIVES: We aim to evaluate long-term cognitive outcome in patients with enlarged ventricles and clinically suspected NPH. METHODS: A neurologist and a neurosurgeon clinically evaluated 468 patients with enlarged ventricles and suspected NPH using radiological methods, intraventricular pressure monitoring, and frontal cortical brain biopsy. The neurologist confirmed final diagnoses after a median follow-up interval of 4.8 years. RESULTS: Altogether, 232 patients (50%) with enlarged ventricles did not fulfill the criteria for shunt surgery. The incidence of dementia among patients with enlarged ventricles, and at least one NPH-related symptom with adequate follow-up data (n = 446) was high, varying from 77 (iNPH, shunt responders) to 141/1000 person-years (non-shunted patients with enlarged ventricles). At the end of the follow-up, 59% of all these patients were demented. The demented population comprised 73% of non-shunted patients with enlarged ventricles, 63% of shunted iNPH patients that did not respond to treatment, and 46% of iNPH patients that were initially responsive to shunting. The most common cause of dementia was Alzheimer's disease (n = 94, 36%), followed by vascular dementia (n = 68, 26%). CONCLUSIONS: One-half of patients with enlarged ventricles and clinically suspected NPH were not shunted after intraventricular pressure monitoring. Dementia caused by various neurodegenerative diseases was frequently seen in patients with ventricular enlargement. Thus, careful diagnostic evaluation in collaboration with neurologists and neurosurgeons is emphasized.

De Novo Aneurysm Formation in Carriers of Saccular Intracranial Aneurysm Disease in Eastern Finland.

BACKGROUND AND PURPOSE: Formation of new (de novo) aneurysms in patients carrying saccular intracranial aneurysm (sIA) disease has been published, but data from population-based cohorts are scarce. METHODS: Kuopio sIA database (http://www.uef.fi/ns) contains all unruptured and ruptured sIA patients admitted to Kuopio University Hospital from its Eastern Finnish catchment population. We studied the incidence and risk factors for de novo sIA formation in 1419 sIA patients with ≥5 years of angiographic follow-up, a total follow-up of 18 526 patient-years. RESULTS: There were 42 patients with a total of 56 de novo sIAs, diagnosed in a median of 11.7 years after the first sIA diagnosis. The cumulative incidence of de novo sIAs was 0.23% per patient-year and that of subarachnoid hemorrhage from a ruptured de novo sIA 0.05% per patient-year. The risk of de novo sIA discovery per patient-year increased with younger age at the first sIA diagnosis: 2.2% in the patients aged <20 years and 0.46% in the patients aged between 20 and 39 years. In Cox regression analysis, smoking history and younger age at the first sIA diagnosis significantly associated with de novo sIA formation, but female sex, multiple sIAs, and sIA family did not. CONCLUSIONS: Patients aged < 40 years at the first sIA diagnosis are in a significant risk of developing de novo sIAs, and they should be scheduled for long-term angiographic follow-up. Smoking increases the risk of de novo sIA formation, suggesting long-term follow-up for smokers. Antismoking efforts are highly recommended for sIA patients.

Hypertension predisposes to the formation of saccular intracranial aneurysms in 467 unruptured and 1053 ruptured patients in Eastern Finland.

OBJECTIVE: Hypertension associates with subarachnoid hemorrhage from saccular intracranial aneurysm (sIA-SAH) when compared to matched controls or general population. Few series compare hypertension in unruptured sIA versus sIA-SAH, so its impact on the sIA disease remains uncertain. METHODS: Kuopio sIA Database ( www.uef.fi/ns ) contains all cases of unruptured and ruptured sIAs admitted to Kuopio University Hospital from its Eastern Finnish catchment population. We compared the age-adjusted incidence of drug-treated hypertension in 467 unruptured and 1053 ruptured sIA patients admitted to Kuopio University Hospital from 1995 to 2007, using the national registry of prescribed medicines. RESULTS: Antihypertensive medication was more frequent in the unruptured (73% versus 62%) with higher age-adjusted incidence. At sIA diagnosis, the sIA-SAH group had more often untreated hypertension (29% versus 23%). The size of unruptured sIAs increased with age at sIA diagnosis, independently of hypertension. Multiple sIAs, familial sIA, and sIA-SAH were not associated with hypertension in multivariate analysis. Results indicate that drug-treated hypertension associates with the formation of sIAs rather than their growth or rupture. CONCLUSION: Hypertension is highly prevalent in the carriers of unruptured sIAs when compared to those with ruptured sIA. Hypertension may associate with the sIA formation, and may predispose to the rupture of sIA if untreated.

Upregulated signaling pathways in ruptured human saccular intracranial aneurysm wall: an emerging regulative role of Toll-like receptor signaling and nuclear factor-κB, hypoxia-inducible factor-1A, and ETS transcription factors.

BACKGROUND: Aneurysmal subarachnoid hemorrhage, almost always from saccular intracranial aneurysm (sIA), is a devastating form of stroke that affects the working-age population. Cellular and molecular mechanisms predisposing to the rupture of the sIA wall are largely unknown. This knowledge would facilitate the design of novel diagnostic tools and therapies for the sIA disease. OBJECTIVE: To investigate gene expression patterns distinguishing ruptured and unruptured sIA. METHODS: We compared the whole-genome expression profile of 11 ruptured sIA wall samples with that of 8 unruptured ones using oligonucleotide microarrays. Signaling pathways enriched in the ruptured sIA walls were identified with bioinformatic analyses. Their transcriptional control was predicted in silico by seeking the enrichment of conserved transcription factor binding sites in the promoter regions of differentially expressed genes. RESULTS: Overall, 686 genes were significantly upregulated and 740 were downregulated in the ruptured sIA walls. Significantly upregulated biological processes included response to turbulent blood flow, chemotaxis, leukocyte migration, oxidative stress, vascular remodeling; and extracellular matrix degradation. Toll-like receptor signaling and nuclear factor-κB, hypoxia-inducible factor-1A, and ETS transcription factor binding sites were significantly enriched among the upregulated genes. CONCLUSION: We identified pathways and candidate genes associated with the rupture of human sIA wall. Our results may provide clues to the molecular mechanism in sIA wall rupture and insight for novel therapeutic strategies to prevent rupture.