@article {448, title = {SLC13A5 is the second gene associated with Kohlsch{\"u}tter-T{\"o}nz syndrome.}, journal = {J Med Genet}, volume = {54}, year = {2017}, month = {2017 01}, pages = {54-62}, abstract = {

BACKGROUND: Kohlsch{\"u}tter-T{\"o}nz syndrome (KTZS) is a rare autosomal-recessive disease characterised by epileptic encephalopathy, intellectual disability and amelogenesis imperfecta (AI). It is frequently caused by biallelic mutations in ROGDI. Here, we report on individuals with ROGDI-negative KTZS carrying biallelic SLC13A5 mutations.

METHODS: In the present cohort study, nine individuals from four families with the clinical diagnosis of KTZS and absence of ROGDI mutations as well as one patient with unexplained epileptic encephalopathy were investigated by clinical and dental evaluation, parametric linkage analysis (one family), and exome and/or Sanger sequencing. Dental histological investigations were performed on teeth from individuals with SLC13A5-associated and ROGDI-associated KTZS.

RESULTS: Biallelic mutations in SLC13A5 were identified in 10 affected individuals. Epileptic encephalopathy usually presents in the neonatal and (less frequently) early infantile period. Yellowish to orange discolouration of both deciduous and permanent teeth, as well as wide interdental spaces and abnormal crown forms are major clinical signs of individuals with biallelic SLC13A5 mutations. Histological dental investigations confirmed the clinical diagnosis of hypoplastic AI. In comparison, the histological evaluation of a molar assessed from an individual with ROGDI-associated KTZS revealed hypocalcified AI.

CONCLUSIONS: We conclude that SLC13A5 is the second major gene associated with the clinical diagnosis of KTZS, characterised by neonatal epileptic encephalopathy and hypoplastic AI. Careful clinical and dental delineation provides clues whether ROGDI or SLC13A5 is the causative gene. Hypersensitivity of teeth as well as high caries risk requires individual dental prophylaxis and attentive dental management.

}, keywords = {Alleles, Amelogenesis Imperfecta, Brain Diseases, Cohort Studies, Dementia, Epilepsy, Exome, Female, Genetic Linkage, Genetic Predisposition to Disease, Humans, Male, Membrane Proteins, Mutation, Nuclear Proteins, Pedigree, Symporters, Tooth}, issn = {1468-6244}, doi = {10.1136/jmedgenet-2016-103988}, author = {Schossig, Anna and Bloch-Zupan, Agn{\`e}s and Lussi, Adrian and Wolf, Nicole I and Raskin, Salmo and Cohen, Monika and Giuliano, Fabienne and Jurgens, Julie and Krabichler, Birgit and Koolen, David A and de Macena Sobreira, Nara Lygia and Maurer, Elisabeth and Muller-Bolla, Mich{\`e}le and Penzien, Johann and Zschocke, Johannes and Kapferer-Seebacher, Ines} } @article {62, title = {A Syndromic Intellectual Disability Disorder Caused by Variants in TELO2, a Gene Encoding a Component of the TTT Complex.}, journal = {Am J Hum Genet}, volume = {98}, year = {2016}, month = {2016 05 05}, pages = {909-918}, abstract = {

The proteins encoded by TELO2, TTI1, and TTI2 interact to form the TTT complex, a co-chaperone for maturation of the phosphatidylinositol 3-kinase-related protein kinases (PIKKs). Here we report six affected individuals from four families with intellectual disability (ID) and neurological and other congenital abnormalities associated with compound heterozygous variants in TELO2. Although their fibroblasts showed reduced steady-state levels of TELO2 and the other components of the TTT complex, PIKK functions were normal in cellular assays. Our results suggest that these TELO2 missense variants result in loss of function, perturb TTT complex stability, and cause an autosomal-recessive syndromic form of ID.

}, keywords = {Adolescent, Carrier Proteins, Child, Female, Humans, Intellectual Disability, Male, Molecular Chaperones, Pedigree, Phosphatidylinositol 3-Kinases, Protein-Serine-Threonine Kinases, Telomere-Binding Proteins}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.03.014}, author = {You, Jing and Sobreira, Nara L and Gable, Dustin L and Jurgens, Julie and Grange, Dorothy K and Belnap, Newell and Siniard, Ashley and Szelinger, Szabolcs and Schrauwen, Isabelle and Richholt, Ryan F and Vallee, Stephanie E and Dinulos, Mary Beth P and Valle, David and Armanios, Mary and Hoover-Fong, Julie} } @article {144, title = {Novel COL2A1 variant (c.619G>A, p.Gly207Arg) manifesting as a phenotype similar to progressive pseudorheumatoid dysplasia and spondyloepiphyseal dysplasia, Stanescu type.}, journal = {Hum Mutat}, volume = {36}, year = {2015}, month = {2015 Oct}, pages = {1004-8}, abstract = {

Progressive pseudorheumatoid dysplasia (PPRD) is a rare, autosomal-recessive condition characterized by mild spondyloepiphyseal dysplasia (SED) and severe, progressive, early-onset arthritis due to WISP3 mutations. SED, Stanescu type, is a vaguely delineated autosomal-dominant dysplasia of unknown genetic etiology. Here, we report three individuals from two unrelated families with radiological features similar to PPRD and SED, Stanescu type who share the same novel COL2A1 variant and were matched following discussion at an academic conference. In the first family, we performed whole-exome sequencing on three family members, two of whom have a PPRD-like phenotype, and identified a heterozygous variant (c.619G>A, p.Gly207Arg) in both affected individuals. Independently, targeted sequencing of the COL2A1 gene in an unrelated proband with a similar phenotype identified the same heterozygous variant. We suggest that the p.Gly207Arg variant causes a distinct type II collagenopathy with features of PPRD and SED, Stanescu type.

}, keywords = {Adolescent, Adult, Child, Collagen Type II, Exome, Female, Humans, Joint Diseases, Male, Osteochondrodysplasias, Pedigree, Polymorphism, Single Nucleotide, Radiography, Sequence Analysis, DNA}, issn = {1098-1004}, doi = {10.1002/humu.22839}, author = {Jurgens, Julie and Sobreira, Nara and Modaff, Peggy and Reiser, Catherine A and Seo, Soo Hyun and Seong, Moon-Woo and Park, Sung Sup and Kim, Ok Hwa and Cho, Tae-Joon and Pauli, Richard M} } @article {275, title = {Mutations in PCYT1A, encoding a key regulator of phosphatidylcholine metabolism, cause spondylometaphyseal dysplasia with cone-rod dystrophy.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 Jan 02}, pages = {105-12}, keywords = {Alleles, Child, Preschool, Choline-Phosphate Cytidylyltransferase, Female, Humans, Infant, Male, Middle Aged, Mutation, Missense, Osteochondrodysplasias, Pedigree, Phosphatidylcholines, Retinitis Pigmentosa}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2013.11.018}, author = {Hoover-Fong, Julie and Sobreira, Nara and Jurgens, Julie and Modaff, Peggy and Blout, Carrie and Moser, Ann and Kim, Ok-Hwa and Cho, Tae-Joon and Cho, Sung Yoon and Kim, Sang Jin and Jin, Dong-Kyu and Kitoh, Hiroshi and Park, Woong-Yang and Ling, Hua and Hetrick, Kurt N and Doheny, Kimberly F and Valle, David and Pauli, Richard M} }