CHCHD10‐related diseases include mitochondrial DNA instability disorder, frontotemporal dementia‐amyotrophic lateral sclerosis (FTD‐ALS) clinical spectrum, late‐onset spinal motor neuropathy (SMAJ), and Charcot–Marie–Tooth disease type 2 (CMT2). Here, we show that CHCHD10 resides with mitofilin, CHCHD3 and CHCHD6 within the “mitochondrial contact site and cristae organizing system” (MICOS) complex. CHCHD10 mutations lead to MICOS complex disassembly and loss of mitochondrial cristae with a decrease in nucleoid number and nucleoid disorganization. Repair of the mitochondrial genome after oxidative stress is impaired in CHCHD10 mutant fibroblasts and this likely explains the accumulation of deleted mtDNA molecules in patient muscle. CHCHD10 mutant fibroblasts are not defective in the delivery of mitochondria to lysosomes suggesting that impaired mitophagy does not contribute to mtDNA instability. Interestingly, the expression of CHCHD10 mutant alleles inhibits apoptosis by preventing cytochrome c release. Synopsis CHCHD10 is found to be part of the MICOS complex. Mutations in CHCHD10, previously associated with ALS, cause MICOS disassembly, loss of mitochondrial cristae, mitochondrial genome repair impairment after oxidative stress, and inhibition of apoptosis. CHCHD10 is found to be a component of the MICOS complex. CHCHD10 mutations disassemble the MICOS complex leading to loss of mitochondrial cristae junctions. Assembly of OXPHOS complexes is impaired leading to respiratory chain deficiency. Nucleoids are disorganized resulting in mtDNA repair impairment after oxidative stress. CHCHD10 mutations do not affect mitophagy. Expression of CHCHD10 mutant alleles prevents cytochrome c release and thus inhibits apoptosis via the caspase‐dependent pathway.

Disrupted in Schizophrenia-1 (DISC1) has been associated with a broad spectrum of mental disorders. DISC1 is a multi-compartmentalized protein found in the cytoplasm, centrosome, nuclei and mostly enriched in mitochondria. In order to shed light on DISC1 mitochondrial function, we have studied its topology within the organelle. We show in here that in mammals DISC1 resides in the "Mitochondrial contact site and Cristae Organizing system" (MICOS) complex, involved in cristae organization. DISC1 knockdown in SH-SY5Y cells causes MICOS disassembly and fragmentation of the mitochondrial morphology network. Moreover, DISC1 depleted cells have decreased mtDNA content and steady state levels of oxidative phosphorylation (OXPHOS) subunits. As a consequence, OXPHOS complexes and supercomplexes are partially disassembled in DISC1 knockdown cells, which suffer severe bioenergetic defects, evidenced by impaired O₂ consumption, ATP synthesis and mitochondrial membrane potential. Transfection of recombinant full-length human DISC1 restores MICOS complex assembly and rescues OXPHOS function, meanwhile overexpression of the DISC1 truncated form Δ597-854, known to be pathogenic, fails to rescue the bioenergetic impairment caused by DISC1 knockdown. These results should contribute to reveal DISC1 physiological function and potential pathogenic role in severe mental illnesses.

Ocular abnormalities have been known to occur in hereditary amyloidotic polyneuropathy since the 1950s. While vitreous opacities and scalloped pupils were described early it has become evident that every component of the eye from the conjunctiva to the retinal vasculature can be involved. Reports from the major centres in Japan, Portugal and Sweden, which primarily treat patients with ATTRV30M, have indicated that with the increased longevity seen in patients treated with liver transplantation the frequency of the more severe eye findings, notably vitreous opacities and subsequent glaucoma, are being detected more frequently. In an attempt to confirm that the experience was similar in a broader range of locales we performed a survey of ten treatment centres in eight countries to determine the frequency of severe ocular abnormalities (vitreous opacities and glaucoma) in 804 patients with V30M disease and whether there was any relationship to treatment with liver transplantation or the transthyretin stabilizer tafamidis. The data indicate that the frequency of these abnormalities increases with increasing duration of disease. In patients broadly matched for duration of disease the frequency was higher in subjects who had undergone liver transplantation than in those who were untreated. Retrospective surveys are subject to a number of potential biases. In this case, the major potential confounders were defining the time of disease onset and physician bias in choice of therapy, particularly regarding the choice of patients and the time in their course when they should undergo liver transplantation, and when and whether they should receive tafamidis. Nonetheless it appears that the incidence of severe ocular abnormalities in V30M subjects from centres around the world is similar to those found in centres in the areas endemic for this variant protein. The incidence increased with duration of disease regardless of therapy with the highest frequencies seen in patients more than ten years after diagnosis who had undergone liver transplantation.

Background: Hereditary transthyretin (TTR) amyloidosis (ATTRv) is a heterogeneous disease with a clinical presentation that varies according to geographical area and TTR mutation. The symptoms of Val50Met-ATTRv are mainly neuropathic and progress to complete disability and death in most untreated patients within 10 to 15 years of diagnosis. The neurological effects may also be accompanied by gastrointestinal impairment, cardiomyopathy, nephropathy and/or ocular deposition. The disease is thus associated with a high degree of patient disability. Accordingly, we aimed to describe the psychosocial burden associated with ATTRv in a group of patients, asymptomatic Val50Met carriers, relatives and caregivers in the endemic focus of the disease in Majorca via a survey addressing various aspects related to psychosocial burden. We performed a an observational, descriptive, cross-sectional and multicentre study in order to analyze the prevalence of self-reported impact of ATTRv disease upon their daily life. In addition to the self-knowledge, fear and burden related to the disease. The survey was disseminated during the regular follow up at the outpatient clinic of the Hospital Universitario Son Llàtzer and during the meetings organized by the Andrade’s Disease patients’ advocacy group from the Balearic Islands. These meetings were attended also by subjects followed up by the Hospital Universitario Son Espases and their caregivers and relatives. Survey was self-administrated. No intervention was done by the investigators. 85 subjects completed the survey: 61 carrying the TTR-V50M variant and 24 caregivers or relatives. Results: Our study revealed that, although most of the population studied had had prior contact with ATTRv through affected relatives, there was still a lack of information regarding disease diagnosis. Fear of the genetic test result and psychological issues were common in our population. Moreover, the disease had a stronger impact on the daily life of our patients than that of our asymptomatic carriers. Autonomic symptoms were the main source of burden for relatives and caregivers. Conclusion: Our survey results show high psychosocial burden associated with Val50Met-ATTRv in our area.

The age of onset (AO) of hereditary ATTR amyloidosis (hATTR) is known to vary between populations, with differing characteristics reported according to AO in endemic/non‐endemic foci. This was a retrospective study of patients with early AO (<50 years) and late AO (≥50 years) hATTR at our center in Mallorca. Data were collected on patient demographics, clinical disease manifestation, and physical symptoms. A total of 95 patients were analyzed, with mean follow‐up of 9 years from diagnosis. The early AO group included 53 patients (33 male) and the late AO group included 42 patients (21 male). Neurologic involvement was the most common initial symptom, although it was significantly more frequent in the late AO vs. early AO group (p = 0.015). Autonomic involvement was observed in 26% of patients in the early AO group, but was rarely observed in the late AO group (5%). During follow up, cardiologic symptoms, renal involvement, and ophthalmologic symptoms were significantly more common in the late AO group (p < 0.05). This retrospective study demonstrates the variation in disease presentation and progression according to AO of hATTR at our Mallorcan center.

Early identification of ATTRv amyloidosis disease onset is still often delayed due to the lack of validated biomarkers of this disease. Light chain neurofilament (NfL) have shown promising results in early diagnosis in this disease, but data is still needed, including with alternative measuring methods. Our aim was to study the levels of NfL measured by ELISA. Furthermore, interstitial matrix metalloproteinase type 1 (MMP-1) serum levels were measured as a potential new biomarker in ATTRv. Serum NfL and MMP-1 were measured using ELISA assays in 90 participants (29 ATTR-V30M patients, 31 asymptomatic V30M-TTR variant carriers and 30 healthy controls). Median NfL levels among ATTRv amyloidosis patients were significantly higher (116 pg/mL vs 0 pg/mL in both comparison groups). The AUC comparing ATTRv amyloidosis patients and asymptomatic carriers was 0.90 and the NfL concentration of 93.55 pg/mL yielded a sensitivity of 79% and a specificity of 87%. NfL levels had a significant positive correlation with NIS values among patients. We found a negative significant correlation between eGFR and NfL levels. Finally, MMP1 levels were not different between groups. Evidence of NfL use for early diagnosis of ATTR-PN amyloidosis is growing. ELISA seems a reliable and available technique for it quantification. Decreased GFR could influence NfL plasma levels.