@article {970, title = {A mutation affecting laminin alpha 5 polymerisation gives rise to a syndromic developmental disorder.}, journal = {Development}, volume = {147}, year = {2020}, month = {2020 06 22}, abstract = {

Laminin alpha 5 (LAMA5) is a member of a large family of proteins that trimerise and then polymerise to form a central component of all basement membranes. Consequently, the protein plays an instrumental role in shaping the normal development of the kidney, skin, neural tube, lung and limb, and many other organs and tissues. Pathogenic mutations in some laminins have been shown to cause a range of largely syndromic conditions affecting the competency of the basement membranes to which they contribute. We report the identification of a mutation in the polymerisation domain of LAMA5 in a patient with a complex syndromic disease characterised by defects in kidney, craniofacial and limb development, and by a range of other congenital defects. Using CRISPR-generated mouse models and biochemical assays, we demonstrate the pathogenicity of this variant, showing that the change results in a failure of the polymerisation of α/β/γ laminin trimers. Comparing these phenotypes with those apparent upon gene deletion in mice provides insights into the specific functional importance of laminin polymerisation during development and tissue homeostasis.

}, keywords = {Amino Acid Sequence, Animals, Animals, Newborn, Child, Preschool, Developmental Disabilities, Fetal Development, Fetus, Humans, Hydronephrosis, Infant, Newborn, Kidney, Laminin, Lung, Male, Mice, Mutation, Polymerization, Protein Domains, Syndrome}, issn = {1477-9129}, doi = {10.1242/dev.189183}, author = {Jones, Lynelle K and Lam, Rachel and McKee, Karen K and Aleksandrova, Maya and Dowling, John and Alexander, Stephen I and Mallawaarachchi, Amali and Cottle, Denny L and Short, Kieran M and Pais, Lynn and Miner, Jeffery H and Mallett, Andrew J and Simons, Cas and McCarthy, Hugh and Yurchenco, Peter D and Smyth, Ian M} } @article {409, title = {Mutations in DYNC2H1, the cytoplasmic dynein 2, heavy chain 1 motor protein gene, cause short-rib polydactyly type I, Saldino-Noonan type.}, journal = {Clin Genet}, volume = {92}, year = {2017}, month = {2017 Aug}, pages = {158-165}, abstract = {

The short-rib polydactyly syndromes (SRPS) are autosomal recessively inherited, genetically heterogeneous skeletal ciliopathies. SRPS phenotypes were historically categorized as types I-IV, with type I first delineated by Saldino and Noonan in 1972. Characteristic findings among all forms of SRP include short horizontal ribs, short limbs and polydactyly. The SRP type I phenotype is characterized by a very small thorax, extreme micromelia, very short, poorly mineralized long bones, and multiple organ system anomalies. To date, the molecular basis of this most severe type of SRP, also known as Saldino-Noonan syndrome, has not been determined. We identified three SRP cases that fit the original phenotypic description of SRP type I. In all three cases, exome sequence analysis revealed compound heterozygosity for mutations in DYNC2H1, which encodes the main component of the retrograde IFT A motor, cytoplasmic dynein 2 heavy chain 1. Thus SRP type I, II, III and asphyxiating thoracic dystrophy (ATD), which also result from DYNC2H1 mutations. Herein we describe the phenotypic features, radiographic findings, and molecular basis of SRP type I.

}, keywords = {Cytoplasmic Dyneins, Ellis-Van Creveld Syndrome, Female, Fetus, Genetic Heterogeneity, Genetic Predisposition to Disease, Humans, Infant, Newborn, Mutation, Phenotype, Pregnancy, Radiography, Short Rib-Polydactyly Syndrome, Whole Exome Sequencing}, issn = {1399-0004}, doi = {10.1111/cge.12947}, author = {Badiner, N and Taylor, S P and Forlenza, K and Lachman, R S and Bamshad, M and Nickerson, D and Cohn, D H and Krakow, D} } @article {208, title = {Brain malformations associated with Knobloch syndrome--review of literature, expanding clinical spectrum, and identification of novel mutations.}, journal = {Pediatr Neurol}, volume = {51}, year = {2014}, month = {2014 Dec}, pages = {806-813.e8}, abstract = {

BACKGROUND: Knobloch syndrome is a rare, autosomal recessive, developmental disorder characterized by stereotyped ocular abnormalities with or without occipital skull deformities (encephalocele, bone defects, and cutis aplasia). Although there is clear heterogeneity in clinical presentation, central nervous system malformations, aside from the characteristic encephalocele, have not typically been considered a component of the disease phenotype.

METHODS: Four patients originally presented for genetic evaluation of symptomatic structural brain malformations. Whole-genome genotyping, whole-exome sequencing, and confirmatory Sanger sequencing were performed. Using immunohistochemical analysis, we investigated the protein expression pattern of COL18A1 in the mid-fetal and adult human cerebral cortex and then analyzed the spatial and temporal changes in the expression pattern of COL18A1 during human cortical development using the Human Brain Transcriptome database.

RESULTS: We identified two novel homozygous deleterious frame-shift mutations in the COL18A1 gene. On further investigation of these patients and their families, we found that many exhibited certain characteristics of Knobloch syndrome, including pronounced ocular defects. Our data strongly support an important role for COL18A1 in brain development, and this report contributes to an enhanced characterization of the brain malformations that can result from deficiencies of collagen XVIII.

CONCLUSIONS: This case series highlights the diagnostic power and clinical utility of whole-exome sequencing technology-allowing clinicians and physician scientists to better understand the pathophysiology and presentations of rare diseases. We suggest that patients who are clinically diagnosed with Knobloch syndrome and/or found to have COL18A1 mutations via genetic screening should be investigated for potential structural brain abnormalities even in the absence of an encephalocele.

}, keywords = {Adolescent, Adult, Cerebral Cortex, Collagen Type XVIII, Consanguinity, Encephalocele, Exome, Female, Fetus, Humans, Male, Mutation, Retinal Degeneration, Retinal Detachment, Young Adult}, issn = {1873-5150}, doi = {10.1016/j.pediatrneurol.2014.08.025}, author = {{\c C}a{\u g}layan, Ahmet Okay and Baranoski, Jacob F and Aktar, Fesih and Han, Wengi and Tuysuz, Beyhan and Guzel, Aslan and Guclu, Bulent and Kaymak{\c c}alan, Hande and Aktekin, Berrin and Akg{\"u}m{\"u}{\c s}, G{\"o}zde Tu{\u g}ce and Murray, Phillip B and Erson-Omay, Emine Z and Caglar, Caner and Bakircioglu, Mehmet and Sakalar, Yildirim Bayezit and Guzel, Ebru and Demir, Nihat and Tuncer, Oguz and Senturk, Senem and Ekici, Bar{\i}{\c s} and Minja, Frank J and {\v S}estan, Nenad and Yasuno, Katsuhito and Bilguvar, Kaya and Caksen, Huseyin and G{\"u}nel, Murat} } @article {217, title = {Molecular findings among patients referred for clinical whole-exome sequencing.}, journal = {JAMA}, volume = {312}, year = {2014}, month = {2014 Nov 12}, pages = {1870-9}, abstract = {

IMPORTANCE: Clinical whole-exome sequencing is increasingly used for diagnostic evaluation of patients with suspected genetic disorders.

OBJECTIVE: To perform clinical whole-exome sequencing and report (1) the rate of molecular diagnosis among phenotypic groups, (2) the spectrum of genetic alterations contributing to disease, and (3) the prevalence of medically actionable incidental findings such as FBN1 mutations causing Marfan syndrome.

DESIGN, SETTING, AND PATIENTS: Observational study of 2000 consecutive patients with clinical whole-exome sequencing analyzed between June 2012 and August 2014. Whole-exome sequencing tests were performed at a clinical genetics laboratory in the United States. Results were reported by clinical molecular geneticists certified by the American Board of Medical Genetics and Genomics. Tests were ordered by the patient{\textquoteright}s physician. The patients were primarily pediatric (1756 [88\%]; mean age, 6 years; 888 females [44\%], 1101 males [55\%], and 11 fetuses [1\% gender unknown]), demonstrating diverse clinical manifestations most often including nervous system dysfunction such as developmental delay.

MAIN OUTCOMES AND MEASURES: Whole-exome sequencing diagnosis rate overall and by phenotypic category, mode of inheritance, spectrum of genetic events, and reporting of incidental findings.

RESULTS: A molecular diagnosis was reported for 504 patients (25.2\%) with 58\% of the diagnostic mutations not previously reported. Molecular diagnosis rates for each phenotypic category were 143/526 (27.2\%; 95\% CI, 23.5\%-31.2\%) for the neurological group, 282/1147 (24.6\%; 95\% CI, 22.1\%-27.2\%) for the neurological plus other organ systems group, 30/83 (36.1\%; 95\% CI, 26.1\%-47.5\%) for the specific neurological group, and 49/244 (20.1\%; 95\% CI, 15.6\%-25.8\%) for the nonneurological group. The Mendelian disease patterns of the 527 molecular diagnoses included 280 (53.1\%) autosomal dominant, 181 (34.3\%) autosomal recessive (including 5 with uniparental disomy), 65 (12.3\%) X-linked, and 1 (0.2\%) mitochondrial. Of 504 patients with a molecular diagnosis, 23 (4.6\%) had blended phenotypes resulting from 2 single gene defects. About 30\% of the positive cases harbored mutations in disease genes reported since 2011. There were 95 medically actionable incidental findings in genes unrelated to the phenotype but with immediate implications for management in 92 patients (4.6\%), including 59 patients (3\%) with mutations in genes recommended for reporting by the American College of Medical Genetics and Genomics.

CONCLUSIONS AND RELEVANCE: Whole-exome sequencing provided a potential molecular diagnosis for 25\% of a large cohort of patients referred for evaluation of suspected genetic conditions, including detection of rare genetic events and new mutations contributing to disease. The yield of whole-exome sequencing may offer advantages over traditional molecular diagnostic approaches in certain patients.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Exome, Female, Fetus, Genetic Diseases, Inborn, Genetic Testing, Genomics, Humans, Incidental Findings, Infant, Infant, Newborn, Male, Molecular Diagnostic Techniques, Mutation, Phenotype, Referral and Consultation, Sequence Analysis, DNA}, issn = {1538-3598}, doi = {10.1001/jama.2014.14601}, author = {Yang, Yaping and Muzny, Donna M and Xia, Fan and Niu, Zhiyv and Person, Richard and Ding, Yan and Ward, Patricia and Braxton, Alicia and Wang, Min and Buhay, Christian and Veeraraghavan, Narayanan and Hawes, Alicia and Chiang, Theodore and Leduc, Magalie and Beuten, Joke and Zhang, Jing and He, Weimin and Scull, Jennifer and Willis, Alecia and Landsverk, Megan and Craigen, William J and Bekheirnia, Mir Reza and Stray-Pedersen, Asbjorg and Liu, Pengfei and Wen, Shu and Alcaraz, Wendy and Cui, Hong and Walkiewicz, Magdalena and Reid, Jeffrey and Bainbridge, Matthew and Patel, Ankita and Boerwinkle, Eric and Beaudet, Arthur L and Lupski, James R and Plon, Sharon E and Gibbs, Richard A and Eng, Christine M} }