Optimal lysosome function requires maintenance of an acidic pH maintained by proton pumps in combination with a counterion transporter such as the Cl À /H þ exchanger, CLCN7 (ClC-7), encoded by CLCN7. The role of ClC-7 in maintaining lysosomal pH has been controversial. In this paper, we performed clinical and genetic evaluations of two children of different ethnicities. Both children had delayed myelination and development, organomegaly, and hypopigmentation, but neither had osteopetrosis. Whole-exome and-genome sequencing revealed a de novo c.2144A>G variant in CLCN7 in both affected children. This p.Tyr715Cys variant, located in the C-terminal domain of ClC-7, resulted in increased outward currents when it was heterologously expressed in Xenopus oocytes. Fibroblasts from probands displayed a lysosomal pH approximately 0.2 units lower than that of control cells, and treatment with chloroquine normalized the pH. Primary fibroblasts from both probands also exhibited markedly enlarged intracellular vacuoles; this finding was recapitulated by the overexpression of human p.Tyr715Cys CLCN7 in control fibroblasts, reflecting the dominant, gain-of-function nature of the variant. A mouse harboring the knock-in Clcn7 variant exhibited hypopigmentation, hepatomegaly resulting from abnormal storage, and enlarged vacuoles in cultured fibroblasts. Our results show that p.Tyr715Cys is a gain-of-function CLCN7 variant associated with developmental delay, organomegaly, and hypopigmentation resulting from lysosomal hyperacidity, abnormal storage, and enlarged intracellular vacuoles. Our data supports the hypothesis that the ClC-7 antiporter plays a critical role in maintaining lysosomal pH.

Patient now 19 years old has intellectual disability, developmental delay, absent speech, seizures, hypotonia, severe motor disability (non-ambulatory), short stature, relative macrocephaly. Patient uses gastric tube for feeding and has gastroesophageal reflux. Facial dysmorphisms include short palpebral fissures, large incisors, full eyebrows. Fingers are short and trident-shaped.Brain MRI revealed progressive cerebral and cerebellar volume loss, hypodensity in the left basal ganglia, unchanged and consistent with a lacune infarct (remote). There is a less conspicuous area of hypodensity on the contralateral side. There are hypodense white matter changes along the periventricular white matter and bilateral centrum semiovale.

In pleiotropic diseases, multiple organ systems are affected causing a variety of clinical manifestations. Here, we report a pleiotropic disorder with a unique constellation of neurological, endocrine, exocrine, and haematological findings that is caused by biallelic MADD variants. MADD, the mitogen-activated protein kinase (MAPK) activating death domain protein, regulates various cellular functions, such as vesicle trafficking, activity of the Rab3 and Rab27 small GTPases, tumour necrosis factor-α (TNF-α)-induced signalling and prevention of cell death. Through national collaboration and GeneMatcher, we collected 23 patients with 21 different pathogenic MADD variants identified by next-generation sequencing. We clinically evaluated the series of patients and categorized the phenotypes in two groups. Group 1 consists of 14 patients with severe developmental delay, endo- and exocrine dysfunction, impairment of the sensory and autonomic nervous system, and haematological anomalies. The clinical course during the first years of life can be potentially fatal. The nine patients in Group 2 have a predominant neurological phenotype comprising mild-to-severe developmental delay, hypotonia, speech impairment, and seizures. Analysis of mRNA revealed multiple aberrant MADD transcripts in two patient-derived fibroblast cell lines. Relative quantification of MADD mRNA and protein in fibroblasts of five affected individuals showed a drastic reduction or loss of MADD. We conducted functional tests to determine the impact of the variants on different pathways. Treatment of patient-derived fibroblasts with TNF-α resulted in reduced phosphorylation of the extracellular signal-regulated kinases 1 and 2, enhanced activation of the pro-apoptotic enzymes caspase-3 and -7 and increased apoptosis compared to control cells. We analysed internalization of epidermal growth factor in patient cells and identified a defect in endocytosis of epidermal growth factor. We conclude that MADD deficiency underlies multiple cellular defects that can be attributed to alterations of TNF-α-dependent signalling pathways and defects in vesicular trafficking. Our data highlight the multifaceted role of MADD as a signalling molecule in different organs and reveal its physiological role in regulating the function of the sensory and autonomic nervous system and endo- and exocrine glands.

The period following heart failure hospitalization (HFH) is a vulnerable time with high rates of death or recurrent HFH.OBJECTIVE To evaluate clinical characteristics, outcomes, and treatment response to vericiguat according to prespecified index event subgroups and time from index HFH in the Vericiguat Global Study in Subjects With Heart Failure With Reduced Ejection Fraction (VICTORIA) trial. DESIGN, SETTING, AND PARTICIPANTSAnalysis of an international, randomized, placebo-controlled trial. All VICTORIA patients had recent (<6 months) worsening HF (ejection fraction <45%). Index event subgroups were less than 3 months after HFH (n = 3378), 3 to 6 months after HFH (n = 871), and those requiring outpatient intravenous diuretic therapy only for worsening HF (without HFH) in the previous 3 months (n = 801). Data were analyzed between May 2, 2020, and May 9, 2020.INTERVENTION Vericiguat titrated to 10 mg daily vs placebo. MAIN OUTCOMES AND MEASURESThe primary outcome was time to a composite of HFH or cardiovascular death; secondary outcomes were time to HFH, cardiovascular death, a composite of all-cause mortality or HFH, all-cause death, and total HFH. RESULTS Among 5050 patients in the VICTORIA trial, mean age was 67 years, 24% were women, 64% were White, 22% were Asian, and 5% were Black. Baseline characteristics were balanced between treatment arms within each subgroup. Over a median follow-up of 10.8 months, the primary event rates were 40.9, 29.6, and 23.4 events per 100 patient-years in the HFH at less than 3 months, HFH 3 to 6 months, and outpatient worsening subgroups, respectively. Compared with the outpatient worsening subgroup, the multivariable-adjusted relative risk of the primary outcome was higher in HFH less than 3 months (adjusted hazard ratio, 1.48; 95% CI, 1.27-1.73), with a time-dependent gradient of risk demonstrating that patients closest to their index HFH had the highest risk. Vericiguat was associated with reduced risk of the primary outcome overall and in all subgroups, without evidence of treatment heterogeneity. Similar results were evident for all-cause death and HFH. Addtionally, a continuous association between time from HFH and vericiguat treatment showed a trend toward greater benefit with longer duration since HFH. Safety events (symptomatic hypotension and syncope) were infrequent in all subgroups, with no difference between treatment arms.CONCLUSIONS AND RELEVANCE Among patients with worsening chronic HF, those in closest proximity to their index HFH had the highest risk of cardiovascular death or HFH, irrespective of age or clinical risk factors. The benefit of vericiguat did not differ significantly across the spectrum of risk in worsening HF.

In this study we investigate the disease etiology in 12 patients with de novo variants in FAR1 all resulting in an amino acid change at position 480 (p.Arg480Cys/His/Leu). METHODS: Following next-generation sequencing and clinical phenotyping, functional characterization was performed in patients' fibroblasts using FAR1 enzyme analysis, FAR1 immunoblotting/immunofluorescence, and lipidomics. RESULTS: All patients had spastic paraparesis and bilateral congenital/juvenile cataracts, in most combined with speech and gross motor developmental delay and truncal hypotonia. FAR1 deficiency caused by biallelic variants results in defective ether lipid synthesis and plasmalogen deficiency. In contrast, patients' fibroblasts with the de novo FAR1 variants showed elevated plasmalogen levels. Further functional studies in fibroblasts showed that these variants cause a disruption of the plasmalogendependent feedback regulation of FAR1 protein levels leading to uncontrolled ether lipid production. CONCLUSION: Heterozygous de novo variants affecting the Arg480 residue of FAR1 lead to an autosomal dominant disorder with a different disease mechanism than that of recessive FAR1 deficiency and a diametrically opposed biochemical phenotype. Our findings show that for patients with spastic paraparesis and bilateral cataracts, FAR1 should be considered as a candidate gene and added to gene panels for hereditary spastic paraplegia, cerebral palsy, and juvenile cataracts.