Microglia are CNS-resident macrophages that scavenge debris and regulate immune responses. Proliferation and development of macrophages, including microglia, requires Colony Stimulating Factor 1 Receptor (CSF1R), a gene previously associated with a dominant adult-onset neurological condition (adult-onset leukoencephalopathy with axonal spheroids and pigmented glia). Here, we report two unrelated individuals with homozygous CSF1R mutations whose presentation was distinct from ALSP. Post-mortem examination of an individual with a homozygous splice mutation (c.1754À1G>C) demonstrated several structural brain anomalies, including agenesis of corpus callosum. Immunostaining demonstrated almost complete absence of microglia within this brain, suggesting that it developed in the absence of microglia. The second individual had a homozygous missense mutation (c.1929C>A [p.His643Gln]) and presented with developmental delay and epilepsy in childhood. We analyzed a zebrafish model (csf1r DM ) lacking Csf1r function and found that their brains also lacked microglia and had reduced levels of CUX1, a neuronal transcription factor. CUX1 þ neurons were also reduced in sections of homozygous CSF1R mutant human brain, identifying an evolutionarily conserved role for CSF1R signaling in production or maintenance of CUX1 þ neurons. Since a large fraction of CUX1 þ neurons project callosal axons, we speculate that microglia deficiency may contribute to agenesis of the corpus callosum via reduction in CUX1 þ neurons. Our results suggest that CSF1R is required for human brain development and establish the csf1r DM fish as a model for microgliopathies. In addition, our results exemplify an under-recognized form of phenotypic expansion, in which genes associated with well-recognized, dominant conditions produce different phenotypes when biallelically mutated.

Congenital disorders of glycosylation are a genetically and clinically heterogeneous group of >130 diseases caused by defects in various steps along glycan modification pathways. The vast majority of these monogenic diseases are autosomal recessive and have multi-systemic manifestations, mainly growth failure, developmental delay, facial dysmorphisms, and variable coagulation and endocrine abnormalities. Carbohydrate deficient transferrin (CDT) and protein-linked glycan analysis with mass spectrometry can diagnose some subtypes of congenital disorders of glycosylation (CDG), while many currently rely on massively parallel genomic sequencing for diagnosis. Early detection is important, as a few of these disorders are treatable. Molecular and biochemical techniques continue to further our understanding of this rapidly expanding group of clinically and genetically diverse disorders.

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BackgroundDue to the potential of human papillomavirus (HPV) vaccination for decreasing cervical cancer rates in Mainland China, where some of the highest incidences in the world have been reported, our study aimed to assess HPV and HPV vaccine knowledge, and to evaluate the effect of a brief educational intervention on HPV knowledge and vaccine acceptability in Chinese undergraduate students and employed women.MethodsThis multi-center, cross-sectional study was conducted across five representative cities of the five main geographical regions of Mainland China. Participants were selected from one comprehensive university and three to four companies in each city for a total of six comprehensive universities and 16 companies. A 62-item questionnaire on HPV knowledge and HPV vaccine acceptability was administered to participants before and after an educational intervention. The intervention consisted of an informative group lecture.ResultsA total of 1146 employed women and 557 female undergraduate students were surveyed between August and November 2011. Baseline HPV knowledge was low among both groups— 320/1146 (28%) of employed women and 66/557 (12%) of students had heard of HPV, while only 237/1146 (21%) of employed women and 40/557 (7.2%) of students knew that HPV is related to cervical cancer. After educational instruction, 947/1061 (89%) of employed women and 193/325 (59%) of students knew the relationship between HPV and cervical cancer (χ2 = 1041.8, p < 0.001 and χ2 = 278.5, p < 0.001, respectively). Post-intervention, vaccine acceptability increased from 881/1146 (77%) to 953/1061 (90%), (p = <0.001) in employed women and 405/557 (73%) in students to 266/325 (82%), (p < 0.001). Women in both groups cited concerns about the HPV vaccine’s safety, efficacy, and limited use to date as reasons for being unwilling to receive vaccination. 502/1146 (44%) of women were willing to vaccinate their children at baseline, which increased to 857/1061 (81%) post-intervention, p < 0.001.ConclusionsIncorporation of our lecture-based education initiative into a government-sponsored or school-based program may improve HPV-related knowledge and HPV vaccine acceptability. Further studies are needed to evaluate and standardize HPV education programs in China.

Wilson disease is an autosomal-recessive disorder of hepatocellular copper deposition caused by pathogenic variants in the copper-transporting gene, ATP7B. Early detection and treatment are critical to prevent lifelong neuropsychiatric, hepatic, and systemic disabilities. Due to the marked heterogeneity in age of onset and clinical presentation, the diagnosis of Wilson disease remains challenging to physicians today. Direct sequencing of the ATP7B gene is the most sensitive and widely used confirmatory testing method, and concurrent biochemical testing improves diagnostic accuracy. More than 600 pathogenic variants in ATP7B have been identified, with single-nucleotide missense and nonsense mutations being the most common, followed by insertions/deletions, and, rarely, splice site mutations. The prevalence of Wilson disease varies by geographic region, with higher frequency of certain mutations occurring in specific ethnic groups. Wilson disease has poor genotype–phenotype correlation, although a few possible modifiers have been proposed. Improving molecular genetic studies continue to advance our understanding of the pathogenesis, diagnosis, and screening for Wilson disease.

IMPORTANCE Juvenile amyotrophic lateral sclerosis (ALS) is a rare form of ALS characterized by age of symptom onset less than 25 years and a variable presentation.OBJECTIVE To identify the genetic variants associated with juvenile ALS. DESIGN, SETTING, AND PARTICIPANTSIn this multicenter family-based genetic study, trio whole-exome sequencing was performed to identify the disease-associated gene in a case series of unrelated patients diagnosed with juvenile ALS and severe growth retardation. The patients and their family members were enrolled at academic hospitals and a government research facility between March 1, 2016, and March 13, 2020, and were observed until October 1, 2020. Whole-exome sequencing was also performed in a series of patients with juvenile ALS. A total of 66 patients with juvenile ALS and 6258 adult patients with ALS participated in the study. Patients were selected for the study based on their diagnosis, and all eligible participants were enrolled in the study. None of the participants had a family history of neurological disorders, suggesting de novo variants as the underlying genetic mechanism. MAIN OUTCOMES AND MEASURESDe novo variants present only in the index case and not in unaffected family members. RESULTSTrio whole-exome sequencing was performed in 3 patients diagnosed with juvenile ALS and their parents. An additional 63 patients with juvenile ALS and 6258 adult patients with ALS were subsequently screened for variants in the SPTLC1 gene. De novo variants in SPTLC1 (p.Ala20Ser in 2 patients and p.Ser331Tyr in 1 patient) were identified in 3 unrelated patients diagnosed with juvenile ALS and failure to thrive. A fourth variant (p.Leu39del) was identified in a patient with juvenile ALS where parental DNA was unavailable. Variants in this gene have been previously shown to be associated with autosomal-dominant hereditary sensory autonomic neuropathy, type 1A, by disrupting an essential enzyme complex in the sphingolipid synthesis pathway.CONCLUSIONS AND RELEVANCE These data broaden the phenotype associated with SPTLC1 and suggest that patients presenting with juvenile ALS should be screened for variants in this gene.

More than 50 individuals with activating variants in the receptor tyrosine kinase PDGFRB have been reported, separated based on clinical features into solitary myofibromas, infantile myofibromatosis, Penttinen syndrome with premature aging and osteopenia, Kosaki overgrowth syndrome, and fusiform aneurysms. Despite their descriptions as distinct clinical entities, review of previous reports demonstrates substantial phenotypic overlap. We present a case series of 12 patients with activating variants in PDGFRB and review of the literature. We describe five patients with PDGFRB activating variants whose clinical features overlap multiple diagnostic entities. Seven additional patients from a large family had variable expressivity and lateonset disease, including adult onset features and two individuals with sudden death. Three patients were treated with imatinib and had robust and rapid response,

COQ2 nephropathy should be suspected in patients presenting with nephrotic syndrome, although less common than disease due to mutations in NPHS1, NPHS2, and WT1. The index of suspicion should remain high, and we suggest that providers consider genetic evaluation even in patients with normal leukocyte CoQ levels, as levels may be within normal range even with significant clinical disease. Early molecular diagnosis and specific treatment are essential in the management of this severe yet treatable condition.