HNRNPA1 de novo Variant Associated with Early Childhood Onset, Rapidly Progressive Generalized Myopathy.

HNRNPA1 variants are known to cause degenerative motoneuron and muscle diseases which manifests in middle age or later. We report on a girl with early childhood onset, rapidly progressive generalized myopathy including ultrastructural findings in line with a proteinopathy. Proteomics of patient-derived muscle and combined screening of genomic data for copy number variations identified a HNRNPA1 de novo intragenic deletion as causative for the phenotype. Our report expands the spectrum of HNRNPA1-related diseases towards early-childhood onset and adds HNRNPA1 to the growing list of ALS and myopathy genes for which certain mutations may cause severe pediatric phenotypes.

Variant of the catalytic cysteine of UFSP2 leads to spondyloepimetaphyseal dysplasia type Di Rocco.

Spondyloepimetaphyseal dysplasia (SEMD) is characterized by vertebral, epiphyseal, and metaphyseal alterations. Patients become predominantly apparent with disproportionate short stature. The genetic background of SEMD is heterogeneous, with different modes of inheritance (autosomal dominant, autosomal recessive, and X-linked disorders). Amongst the genes in which variants are known to cause SEMD, UFM1-specific protease 2 (UFSP2) encodes a cysteine protease involved in the maturation of Ubiquitin-fold modifier 1 (UFM1). Heterozygous pathogenic variants affecting the C-terminal catalytic domain of UFSP2 are related to two entities of skeletal dysplasia, Beukes hip dysplasia (BHD) and SEMD type Di Rocco (SEMDDR). This is the first report of a de novo heterozygous variant affecting the catalytic Cys302 residue of UFSP2 (NM_018359.3:c.905G>C, p.(Cys302Ser)) causing SEMDDR. According to previously described patients with SEMDDR, our patient presented with disproportionate short stature, genu varum, gait instability, and radiologically detected epiphyseal and metaphyseal alterations. Additionally, a bell-shaped thorax, lumbar hyperlordosis, muscular hypotonia, and coxa vara were observed in the patient described in this study. Our findings underline the fundamental importance of an intact catalytic triad of the human UFSP2 for normal skeletal development and extend the phenotypical features of patients with UFSP2-related skeletal dysplasia.

Abbreviated MRI for Comprehensive Regional Lymph Node Staging during Pre-Operative Breast MRI.

BACKGROUND: The detection of regional lymph node metastases (LNM), in particular significant LNM (≥N2), is important to guide treatment decisions in women with breast cancer. The purpose of this study was to determine whether a coronal pulse sequence as part of pre-operative breast MRI is useful to identify women without significant LNM. MATERIAL: Retrospective study between January 2017 and December 2019 on 414 consecutive women with breast cancer who underwent pre-operative breast MRI on a 1.5 T system. For lymph node (LN) staging, a coronal pre-contrast non-fat-suppressed T1-weighted TSE sequence was acquired with the system's built-in body coil, covering the chest wall; acquisition time 3:12 min. Two radiologists rated the likelihood of LNM on a 3-point scale (absent/possible/present). Validation was obtained by histology from sentinel LN biopsy, axillary LN dissection, and/or PET/CT. RESULTS: 368/414 women were staged to have no or non-significant LNM (pN0 in 282/414, pN1 in 86/414), and significant LNM (≥pN2) in 46/414. For identification of women with significant LNM, MRI was true-positive in 42/46, false-negative in 4/46, true-negative in 327/368, and false-positive in 41/83, the latter mostly caused by women with N1-disease (38/41), yielding an NPV and PPV for significant LNM of 98.8% [95%-CI: 97.0-100%] and 50.6% [43.1-58.1%], respectively. CONCLUSIONS: A 3 min coronal T1-weighted pulse sequence covering the chest wall as part of pre-operative breast MRI is useful to rule out significant LNM with high NPV. Where MRI staging is positive for significant LNM, additional work-up is indicated to improve the distinction of N1 and N2 disease.

Four genes encoding different type I signal peptidases are organized in a cluster in Streptomyces lividans TK21.

Four adjacent genes (sipW, sipX, sipY and sipZ) encoding different type I signal peptidases, were isolated on a 7860 bp DNA fragment from Streptomyces lividans TK21. Three of the sip genes constitute an operon and the fourth is the first gene of another operon encompassing three additional, unrelated genes. A DNA fragment containing the four sip genes complemented an Escherichia coli type I signal peptidase mutant when cloned in a multicopy plasmid. Clustering of four different type I signal peptidase genes seems, so far, to be a unique feature of Streptomyces.

Site-specific integration of bacteriophage VWB genome into Streptomyces venezuelae and construction of a VWB-based integrative vector.

The temperate bacteriophage VWB integrates into the chromosome of Streptomyces venezuelae ETH14630 via site-specific integration. Following recombination of the VWB attP region with the chromosomal attB sequence, the host-phage junctions attL and attR are formed. Nucleotide sequence analysis of attP, attB, attL and attR revealed a 45 bp common core sequence. In attB this 45 bp sequence consists of the 3' end of a putative tRNA Arg(AGG) gene with a 3'-terminal CCA sequence which is typical for prokaryotic tRNAs. Phage DNA integration restores the putative tRNA Arg(AGG) gene in attL. However, following recombination the CCA sequence is missing as is the case for most Streptomyces tRNA genes described so far. Adjacent to VWB attP, an ORF encoding a 427 aa protein was detected. The C-terminal region of this protein shows high similarity to the conserved C-terminal domain of site-specific recombinases belonging to the integrase family. To prove the functionality of this putative integrase gene (int), an integrative vector pKT02 was constructed. This vector consists of a 2.3 kb HindIII-SphI restriction fragment of VWB DNA containing attP and int cloned in a non-replicative Escherichia coli vector carrying a thiostrepton-resistance (tsr) gene. Integration of pKT02 was obtained after transformation of Streptomyces venezuelae ETH14630 and Streptomyces lividans TK24 protoplasts. This vector will thus be useful for a number of additional Streptomyces species in which a suitable tRNA gene can be functional as integration site.