Townes–Brocks syndrome

Townes–Brocks syndrome
Classification and external resources
OMIM	107480
DiseasesDB	32163

Townes–Brocks syndrome^[1] (TBS) is a rare genetic disease that affects fewer than 200 people in the entire world.^[2] It affects both males and females equally.^[3] The condition was first identified in 1972.^[3]

Contents 1 Symptoms 2 Causes 3 External links 4 Notes

Symptoms

TBS sufferers may have the following symptoms:^[4]

• Abnormalities of the external ears (unusually large or small, unusually shaped, sometimes with sensorineural hearing loss or deafness due to lesions or dysfunctions of part of the internal ear or its nerve tracts and centers or conductive hearing loss from the external or middle ear), dysplastic ears, lop ear (over-folded ear helix), preauricular tags or pits (a rudimentary tag of ear tissue typically located just in front of the ear).

• Anorectal malformations, including imperforate anus/absence of an anal opening, rectovaginal fistula, anal stenosis, unusually placed anus.

• Renal abnormalities, sometimes leading to impaired renal function or renal failure, including hypoplastic kidneys (underdeveloped), multicystic kidneys, dyspastic kidneys.

• Heart abnormalities, including tetralogy of fallot and defects of the ventricular septum.

• Hand and foot abnormalities, such as hypoplastic thumbs, fingerlike thumbs, syndactyly (webbed fingers/toes), fusion of the wrist bones, overlapping foot and/or toe bones.

Learning difficulties have been reported in some children with TBS. For others, intelligence is within the normal range.

These abnormalities, which are present prenatally, can range from minor to severe, and as with similar disorders, most individuals with this condition have some, but not all, of these traits.

Causes

TBS is an autosomal dominant involving the a mutation of the gene SALL1, which encodes a transcriptional repressor which interacts with TRF1/PIN2 and localizes to pericentromeric heterochromatin. The clinical features of TBS overlap with VATER and VACTERL associations, oculo-auriculo-vertebral (OAV) spectrum, branchio-oto-renal (BOR) syndrome, and Fanconi anemia and other 'anus-hand-ear' syndromes.^[5]

Although some symptoms can be life-threatening, many people diagnosed with Townes-Brocks Syndrome live a normal lifespan.^[3]

External links

• GeneReview/NCBI/NIH/UW entry on Townes-Brocks Syndrome

Notes

1. ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. pp. 894. ISBN 1-4160-2999-0. 
2. ^ Faces of Children
3. ^ ^{a b c} Contact a Family
4. ^ National Organization for Rare Diseases
5. ^ GeneDX

Genetic disorder, protein biosynthesis: Transcription factor/coregulator deficiencies (1) Basic domains 1.2: Feingold syndrome · Saethre-Chotzen syndrome 1.3: Tietz syndrome (2) Zinc finger DNA-binding domains 2.1 (Intracellular receptor): Thyroid hormone resistance · Androgen insensitivity syndrome (PAIS, MAIS, CAIS) · Kennedy's disease · PHA1AD pseudohypoaldosteronism · Estrogen insensitivity syndrome · X-linked adrenal hypoplasia congenita · MODY 1 · Familial partial lipodystrophy 3 · SF1 XY gonadal dysgenesis 2.2: Barakat syndrome · Tricho–rhino–phalangeal syndrome 2.3: Greig cephalopolysyndactyly syndrome/Pallister-Hall syndrome · Denys–Drash syndrome · Duane-radial ray syndrome · MODY 7 · MRX 89 · Townes–Brocks syndrome · Acrocallosal syndrome · Myotonic dystrophy 2 2.5: Autoimmune polyendocrine syndrome type 1 (3) Helix-turn-helix domains 3.1: ARX (Ohtahara syndrome, Lissencephaly X2) · HLXB9 (Currarino syndrome) · HOXD13 (SPD1 Synpolydactyly) · IPF1 (MODY 4) · LMX1B (Nail–patella syndrome) · MSX1 (Tooth and nail syndrome, OFC5) · PITX2 (Axenfeld syndrome 1) · POU4F3 (DFNA15) · POU3F4 (DFNX2) · ZEB1 (Posterior polymorphous corneal dystrophy 3, Fuchs' dystrophy 3) · ZEB2 (Mowat-Wilson syndrome) 3.2: PAX2 (Papillorenal syndrome) · PAX3 (Waardenburg syndrome 1&3) · PAX4 (MODY 9) · PAX6 (Gillespie syndrome, Coloboma of optic nerve) · PAX8 (Congenital hypothyroidism 2) · PAX9 (STHAG3) 3.3: FOXC1 (Axenfeld syndrome 3, Iridogoniodysgenesis, dominant type) · FOXC2 (Lymphedema–distichiasis syndrome) · FOXE1 (Bamforth–Lazarus syndrome) · FOXE3 (Anterior segment mesenchymal dysgenesis) · FOXF1 (ACD/MPV) · FOXI1 (Enlarged vestibular aqueduct) · FOXL2 (Premature ovarian failure 3) · FOXP3 (IPEX) 3.5: IRF6 (Van der Woude syndrome, Popliteal pterygium syndrome) (4) β-Scaffold factors with minor groove contacts 4.2: Hyperimmunoglobulin E syndrome 4.3: Holt-Oram syndrome · Li-Fraumeni syndrome · Ulnar–mammary syndrome 4.7: Campomelic dysplasia · MODY 3 · MODY 5 · SF1 (SRY XY gonadal dysgenesis, Premature ovarian failure 7) · SOX10 (Waardenburg syndrome 4c, Yemenite deaf-blind hypopigmentation syndrome) 4.11: Cleidocranial dysostosis (0) Other transcription factors 0.6: Kabuki syndrome Ungrouped TCF4 (Pitt-Hopkins syndrome) · ZFP57 (TNDM1) · TP63 (Rapp–Hodgkin syndrome/Hay–Wells syndrome/Ectrodactyly–ectodermal dysplasia–cleft syndrome 3/Limb–mammary syndrome/OFC8) Transcription coregulators coactivator: CREBBP (Rubinstein–Taybi syndrome) corepressor: HR (Atrichia with papular lesions) see also transcription factors B structural (perx, skel, cili, mito, nucl, sclr) · DNA/RNA/protein synthesis (drep, trfc, tscr, tltn) · membrane (icha, slcr, atpa, abct, othr) · transduction (iter, csrc, itra), trfk