Undiagnosed Hackathon Ends Diagnostic Odyssey in a Patient With DNA2-Related Rothmund-Thomson Syndrome.

Rothmund-Thomson syndrome (RTS) is an ultra-rare, genetically heterogeneous autosomal recessive genodermatosis characterized by poikiloderma, sparse hair and eyebrows, photosensitivity, and short stature. The recently described RTS type 4 (RTS-4), caused by biallelic variants in the DNA2 gene, is associated with additional distinctive features such as microphthalmia, corneal opacity, congenital cataracts (rather than juvenile), and hypothyroidism. To date, eight individuals with RTS-4 have been reported, all carrying a deep intronic variant in DNA2 (ENST00000358410.

RNA sequencing driven diagnosis expands the phenotypic spectrum of NBAS deficiency.

One in 10 individuals has a rare disease, with exome and genome sequencing yielding an overall diagnostic rate of approximately 30 %. RNA sequencing can augment genome analysis and improve diagnosis. We present a young woman with global developmental delay, poor growth, distinctive facial features, osteopenia, premature ovarian insufficiency, and ocular abnormalities who had non-diagnostic genome sequencing.

Mitochondrial trifunctional protein deficiency caused by a deep intronic deletion leading to aberrant splicing.

Trifunctional protein deficiency (TFP) is a disorder of fatty acid beta-oxidation associated with metabolic, cardiac, and liver dysfunction in severe forms. We present two siblings diagnosed by newborn screening and confirmed by biochemical testing at birth. Their clinical course was complicated by recurrent rhabdomyolysis, retinopathy, and hypoparathyroidism.

Systematic analysis of physical examination characteristics of 94 individuals with Joubert syndrome: Keys to suspecting the diagnosis.

Joubert syndrome (JS) is a neurodevelopmental disorder characterized by hypotonia and developmental delay, as well as the obligatory molar tooth sign on brain imaging. Since hypotonia and developmental delay are nonspecific features, there must be a high level of clinical suspicion of JS so that the diagnostic brain imaging and/or molecular testing for the >38 genes associated with JS is/are obtained. The goal of this study was to analyze clinical photographs of a cohort of patients with JS to define a list of physical examination features that should prompt investigation for JS.

Generation and characterization of four Chediak-Higashi Syndrome (CHS) induced pluripotent stem cell (iPSC) lines.

Chediak-Higashi Syndrome (CHS) is a lysosome-related organelle (LRO) disorder caused by biallelic mutations in the lysosomal trafficking regulator gene, LYST. The clinical features of CHS include oculocutaneous albinism, primary immunodeficiency, bleeding diathesis, risk for development of hemophagocyticlymphohistiocytosis,and progressive neurological problems. The pathophysiological mechanisms underlying this disease are unknown, so developing therapeutic options remains challenging.

Deficiency in the endocytic adaptor proteins PHETA1/2 impairs renal and craniofacial development.

A critical barrier in the treatment of endosomal and lysosomal diseases is the lack of understanding of the functions of the putative causative genes. We addressed this by investigating a key pair of endocytic adaptor proteins, PH domain-containing endocytic trafficking adaptor 1 and 2 (PHETA1/2; also known as FAM109A/B, Ses1/2, IPIP27A/B), which interact with the protein product of , the causative gene for Lowe syndrome. Here, we conducted the first study of PHETA1/2 , utilizing the zebrafish system.

Cysteinyl-tRNA Synthetase Mutations Cause a Multi-System, Recessive Disease That Includes Microcephaly, Developmental Delay, and Brittle Hair and Nails.

Aminoacyl-tRNA synthetases (ARSs) are essential enzymes responsible for charging tRNA molecules with cognate amino acids. Consistent with the essential function and ubiquitous expression of ARSs, mutations in 32 of the 37 ARS-encoding loci cause severe, early-onset recessive phenotypes. Previous genetic and functional data suggest a loss-of-function mechanism; however, our understanding of the allelic and locus heterogeneity of ARS-related disease is incomplete.

Quantification of lectin fluorescence in GNE myopathy muscle biopsies.

Introduction: GNE myopathy is an adult-onset muscle disorder characterized by impaired sialylation of (muscle) glycans, detectable by lectin histochemistry. We describe a standardized method to quantify (lectin-) fluorescence in muscle sections, applicable for diagnosis and response to therapy for GNE myopathy.

Methods: Muscle sections were fluorescently labeled with the sialic acid-binding Sambucus nigra agglutinin (SNA) lectin and antibodies to sarcolemma residence protein caveolin-3 (CAV-3).

Safety, pharmacokinetics and sialic acid production after oral administration of N-acetylmannosamine (ManNAc) to subjects with GNE myopathy.

GNE myopathy is a rare, autosomal recessive, inborn error of sialic acid metabolism, caused by mutations in GNE, the gene encoding UDP-N-acetyl-glucosamine-2-epimerase/N-acetylmannosamine kinase. The disease manifests as an adult-onset myopathy characterized by progressive skeletal muscle weakness and atrophy. There is no medical therapy available for this debilitating disease.

Exome analysis of Smith-Magenis-like syndrome cohort identifies de novo likely pathogenic variants.

Smith-Magenis syndrome (SMS), a neurodevelopmental disorder characterized by dysmorphic features, intellectual disability (ID), and sleep disturbances, results from a 17p11.2 microdeletion or a mutation in the RAI1 gene. We performed exome sequencing on 6 patients with SMS-like phenotypes but without chromosomal abnormalities or RAI1 variants.

Muscle Weakness and Fibrosis Due to Cell Autonomous and Non-cell Autonomous Events in Collagen VI Deficient Congenital Muscular Dystrophy.

Congenital muscular dystrophies with collagen VI deficiency are inherited muscle disorders with a broad spectrum of clinical presentation and are caused by mutations in one of COL6A1-3 genes. Muscle pathology is characterized by fiber size variation and increased interstitial fibrosis and adipogenesis. In this study, we define critical events that contribute to muscle weakness and fibrosis in a mouse model with collagen VI deficiency.

Sialylation of Thomsen-Friedenreich antigen is a noninvasive blood-based biomarker for GNE myopathy.

Aim: The exact pathomechanism of GNE myopathy remains elusive, but likely involves aberrant sialylation. We explored sialylation status of blood-based glycans as potential disease markers.

Methods: We employed immunoblotting, lectin histochemistry and mass spectrometry.

Allele-specific Gene Silencing of Mutant mRNA Restores Cellular Function in Ullrich Congenital Muscular Dystrophy Fibroblasts.

Ullrich congenital muscular dystrophy (UCMD) is an inherited muscle disorder characterized clinically by muscle weakness, distal joint hyperlaxity, and proximal joint contractures. Sporadic and recessive mutations in the three collagen VI genes, COL6A1, COL6A2, and COL6A3, are reported to be causative. In the sporadic forms, a heterozygous point mutation causing glycine substitution in the triple helical domain has been identified in higher rate.

1,25-(OH)2D-24 Hydroxylase (CYP24A1) Deficiency as a Cause of Nephrolithiasis.

Background And Objectives: Elevated serum vitamin D with hypercalciuria can result in nephrocalcinosis and nephrolithiasis. This study evaluated the cause of excess 1,25-dihydroxycholecalciferol (1α,25(OH)2D3) in the development of those disorders in two individuals.

Design, Setting, Participants, & Measurements: Two patients with elevated vitamin D levels and nephrocalcinosis or nephrolithiasis were investigated at the National Institutes of Health (NIH) Clinical Center and the NIH Undiagnosed Diseases Program, by measuring calcium, phosphate, and vitamin D metabolites, and by performing CYP24A1 mutation analysis.

Lysosomal myopathies: an excessive build-up in autophagosomes is too much to handle.

Lysosomes are membrane-bound acidic organelles that contain hydrolases used for intracellular digestion of various macromolecules in a process generally referred to as autophagy. In normal skeletal and cardiac muscles, lysosomes usually appear morphologically unremarkable and thus are not readily visible on light microscopy. In distinct neuromuscular disorders, however, lysosomes have been shown to be structurally abnormal and functionally impaired, leading to the accumulation of autophagic vacuoles in myofibers.