👤 Pierre Besson

Electroencephalography (EEG) and magnetoencephalography (MEG), two of the most widely used tools for studying human brain dynamics, are thought to have varying spatial resolutions. Here, we simultaneously recorded EEG and MEG data from 14 participants to directly compare their sensitivities - at both the sensor and source levels - to the auditory Mismatch Negativity (MMN in EEG and MMNm in MEG) elicited by pitch deviants. At the sensor level, we observed that negative components emerged in early (100-190 ms) and late (260-420 ms) latency windows. These responses displayed a fronto-central distribution in EEG and a centro-parietal distribution in MEG. MEG also yielded larger effect sizes than EEG, likely reflecting differences in signal-to-noise ratio between MEG and EEG. At the source level, our findings support the involvement of a fronto-temporal auditory MMN network. Both EEG and MEG identified generators in the superior temporal gyrus, Heschl's gyrus, interior frontal gyrus, and insular regions. Notably, EEG source localization revealed additional generators in the left superior temporal sulcus not detected by MEG, whereas MEG identified late components generators in the right hemisphere that were not observed with EEG. Taken together, these results suggest that EEG and MEG may provide complementary perspectives on auditory processing. However, given the inherent complexity of comparing data acquired with different methodologies and the limited sample size, our conclusions should be regarded as preliminary. Show less

To examine the changes in diagnostic practices and clinical management of patients with 5α-reductase type 2 (SRD5A2) or 17β-hydroxysteroid dehydrogenase type 3 (HSD17B3) deficiency since molecular diagnoses became available. Clinical, laboratory, and therapeutic data were retrieved from the medical records of 52 patients with a molecular diagnosis of SRD5A2 (n = 31) or HSD17B3 (n = 21) deficiency. Temporal trends regarding age at assessment and initial sex assignment over 1994-2020 were qualitatively analyzed. Age at molecular diagnosis was compared between two subgroups of patients according to their year of birth. Fifty-eight percent (n = 30) patients were diagnosed during the perinatal period, 33% (n = 17) during infancy, and 9% (n = 5) during adolescence or adulthood. Over the studied period, the patients' age at initial assessment and diagnosis frankly decreased. The median (range) age at diagnostic confirmation was 10.5 (0-53.2) years for patients born before 2007 and 0.4 (0-9.3) years for those born in 2007 or later (P = 0.029). Genetic testing identified 27 different variants for the SRD5A2 gene (30% novel, n = 8) and 18 for the HSD17B3 gene (44% novel, n = 8). Before 2002, most patients were initially assigned as females (95%, n = 19), but this proportion dropped for those born later (44%, n = 14; P < 0.001). The influence of initial genital appearance on these decisions seemingly decreased in the most recent years. Therapeutic interventions differed according to the sex of rearing. Ten percent (n = 2) patients requested female-to-male reassignment during adulthood. This study showed, over the past two decades, a clear trend toward earlier diagnosis and assignment of affected newborns as males. Show less

Urea cycle disorders (UCD) are rare diseases that usually affect neonates or young children. During decompensations, hyperammonemia is neurotoxic, leading to severe symptoms and even coma and death if not treated rapidly. The aim was to describe a cohort of patients with adult onset of UCDs in a multicentric, retrospective and descriptive study of French adult patients with a diagnosis after 16 years of age of UCDs due to a deficiency in one of the 6 enzymes (arginase, ASL, ASS, CPS1, NAGS, OTC) or the two transporters (ORNT1 or citrin). Seventy-one patients were included (68% female, 32% male). The diagnosis was made in the context of (a) a metabolic decompensation (42%), (b) family history (55%), or (c) chronic symptoms (3%). The median age at diagnosis was 33 years (range 16-86). Eighty-nine percent of patients were diagnosed with OTC deficiency, 7% CPS1 deficiency, 3% HHH syndrome and 1% argininosuccinic aciduria. For those diagnosed during decompensations (including 23 OTC cases, mostly female), 89% required an admission in intensive care units. Seven deaths were attributed to UCD-6 decompensations and 1 epilepsy secondary to inaugural decompensation. This is the largest cohort of UCDs diagnosed in adulthood, which confirms the triad of neurological, gastrointestinal and psychiatric symptoms during hyperammonemic decompensations. We stress that females with OTC deficiency can be symptomatic. With 10% of deaths in this cohort, UCDs in adults remain a life-threatening condition. Physicians working in adult care must be aware of late-onset presentations given the implications for patients and their families. Show less

In most animals, sex determination occurs at conception, when sex chromosomes are segregated following Mendelian laws. However, in multiple reptiles and fishes, this genetic sex can be overridden by external factors after fertilization or birth. In some species, the genetic sex may also be governed by multiple genes, further limiting our understanding of sex determination in such species. We used the European sea bass ( Show less

Loss of epithelial polarity and gain in invasiveness by carcinoma cells are critical events in the aggressive progression of cancers and depend on phenotypic transition programs such as the epithelial-to-mesenchymal transition (EMT). Many studies have reported the aberrant expression of voltage-gated sodium channels (Na Show less

Idiopathic scoliosis (IS) is a spine deformity that affects approximately 3% of the population. The underlying causes of IS are not well understood, although there is clear evidence that there is a genetic component to the disease. Genetic mapping studies suggest high genetic heterogeneity, but no IS disease-causing gene has yet been identified. Here, genetic linkage analyses combined with exome sequencing identified a rare missense variant (p.A446T) in the centriolar protein gene POC5 that cosegregated with the disease in a large family with multiple members affected with IS. Subsequently, the p.A446T variant was found in an additional set of families with IS and in an additional 3 cases of IS. Moreover, POC5 variant p.A455P was present and linked to IS in one family and another rare POC5 variant (p.A429V) was identified in an additional 5 cases of IS. In a zebrafish model, expression of any of the 3 human IS-associated POC5 variant mRNAs resulted in spine deformity, without affecting other skeletal structures. Together, these findings indicate that mutations in the POC5 gene contribute to the occurrence of IS. Show less