The COVID‐19 pandemic has led to a reorganization of health systems to prioritize the fight against the virus. The adoption of social distancing interfered with the flow of existing policies, and may thus negatively affect the most vulnerable groups, such as the rare disease community. Aimming at characterizing the perception of the impact of COVID‐19 on the health care of the Brazilian rare disease community, an online questionnaire addressed to patients with rare diseases and their caregivers was disseminated in the Brazilian territory between June 1st to July 5th, 2020. The questions dealt with the sanitary measures adopted; access to medical services; and mental suffering during the pandemic. The survey was answered by 1,466 participants (<18 yo = 53.3%) representing 192 rare diseases. Regarding physical distancing, 1,372 (93.6%) participants did not leave their residence, or did so only when essential; 1,321 (90.1%) always wore masks when leaving home. 1,042 (71.1%) and 995 (67.9%) participants, respectively, referred medical genetics appointments and rehabilitation therapies were postponed/canceled. Telemedicine was experienced by 1,026 (70%), and 68.3% agreed this is a good strategy for health care. Patients with Inborn Errors of Metabolism (IEM, n = 624, 42.5%) appear to have more access to information and ability to overcome difficulties, and feel less threatened, lonely and depressed than the non‐IEM group ( p < .05). There was an increment of the rare disease patients' vulnerability in the pandemic scenario. The cooperation of patients/caregivers along with adaptation of the health system is crucial and may be so even post‐pandemic.

Purpose Pathogenic variants in GNPTAB and GNPTG, encoding different subunits of GlcNAc-1-phosphotransferase, cause mucolipidosis (ML) II, MLIII alpha/beta, and MLIII gamma. This study aimed to investigate the cellular and molecular bases underlying skeletal abnormalities in patients with MLII and MLIII. Methods We analyzed bone biopsies from patients with MLIII alpha/beta or MLIII gamma by undecalcified histology and histomorphometry. The skeletal status of Gnptgkoand Gnptab-deficient mice was determined and complemented by biochemical analysis of primary Gnptgko bone cells. The clinical relevance of the mouse data was underscored by systematic urinary collagen crosslinks quantification in patients with MLII, MLIII alpha/beta, and MLIII gamma. Results The analysis of iliac crest biopsies revealed that bone remodeling is impaired in patients with GNPTAB-associated MLIII alpha/beta but not with GNPTG-associated MLIII gamma. Opposed to Gnptab-deficient mice, skeletal remodeling is not affected in Gnptgko mice. Most importantly, patients with variants in GNPTAB but not in GNPTG exhibited increased bone resorption. Conclusion The gene-specific impact on bone remodeling in human individuals and in mice proposes distinct molecular functions of the GlcNAc-1-phosphotransferase subunits in bone cells. We therefore appeal for the necessity to classify MLIII based on genetic in addition to clinical criteria to ensure appropriate therapy.

Citrullinemia type 1 (CTLNI), long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD), and mut 0 methylmalonic acidemia (mut 0 MMA) are inborn errors of metabolism (IEMs) associated with sudden unexpected death in infancy (SUDI). Its most common pathogenic variants are: c.1168G>A (CTLNI, ASS1 gene), c.1528G>C (LCHADD, HADHA gene), c.655A>T and c.1106G>A (mut 0 MMA, MUT gene). Considering the absence of estimates regarding the incidence of these diseases in Brazil, this study sought to investigate the prevalence of its main pathogenic variants in a healthy population in the southern region of the country. A total of 1,000 healthy subjects from Rio Grande do Sul were included. Genotyping was performed by real-time PCR. Individuals found to be heterozygous for c.1528G>C underwent further acylcarnitine profile analysis by tandem mass spectrophotometry. Allele and genotype frequencies were calculated considering Hardy-Weinberg equilibrium. The c.1528G>C variant was detected in heterozygosity in two subjects (carrier frequency = 1:500; allele frequency = 0.001; minimum prevalence of LCHADD = 1: 1,000,000), whose acylcarnitine profiles were normal. Variants c.1168G>A, c.655A>T, and c.1106G>A were not identified. These results denote the rarity of these IEMs in Southern Brazil, highlighting the need to expand the investigation of IEMs in relation to infant morbidity and mortality within the country.