title: Solitary thyroid nodule as presenting symptom of Pendred syndrome caused by a novel splice-site mutation in intron 8 of the SLC26A4 gene.
abstract: Thyroid nodules are a rare occurrence in children but represent an important clinical problem because of the possibility of malignancy. We report the case of a 4-year-old boy with sensorineural deafness, who presented with a painless mass in the right anterior cervical region. Cervical ultrasound demonstrated a solid nodule (1.4 x 2.5 x 1.7 cm) in the right thyroid lobe. Thyroid function tests revealed compensated hypothyroidism (free T4 1.0 ng/dl; TSH 57 mIU/l) with no detectable thyroid antibodies. A 99mTc thyroid scan showed a generalised slightly increased tracer retention (4.6%) with an enlarged right lobe, without distinct nodules. A fine-needle aspiration biopsy revealed normal follicular cells. The boy was treated with l-thyroxine which resulted in a complete clinical and sonographical disappearance of the nodule. A CT scan of temporal bones revealed a bilaterally enlarged vestibular aqueduct with Mondini malformation of the cochlea. The combination of all these symptoms suggested the diagnosis of Pendred syndrome (PDS), a disorder characterised by congenital sensorineural hearing loss and a variable degree of thyromegaly due to mutations in the SLC26A4/PDSgene. DNA analysis disclosed a so far unreported homozygous splice site mutation (1002-4 C>G) in intron 8 of the SLC26A4 gene confirming this diagnosis.
  
  
  CONCLUSIONS
  a solitary thyroid nodule may therefore be another presenting symptom of thyroid involvement in Pendred syndrome
authors.affiliation: Department of Paediatrics, Virga Jesseziekenhuis, Stadsomvaart 11, 3500 Hasselt, Belgium. guy.massa@planetinternet.be
authors.forename: Guy
authors.initials: G
authors.lastname: Massa
authors.forename: Nele
authors.initials: N
authors.lastname: Jaenen
authors.forename: Sebastien Janssens
authors.initials: SJ
authors.lastname: de Varebeke
authors.forename: Nils
authors.initials: N
authors.lastname: Peeters
authors.forename: Wim
authors.initials: W
authors.lastname: Wuyts
mesh_terms: D002352:Carrier Proteins / Q000235:genetics*; D002675:Child, Preschool; D004252:DNA Mutational Analysis; D004587:Electrophoresis, Agar Gel; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006801:Humans; D007438:Introns; D008297:Male; D026901:Membrane Transport Proteins; D022821:RNA Splice Sites; D000076988:Sulfate Transporters; D013577:Syndrome; D016606:Thyroid Nodule / Q000209:etiology*
chemical_list: D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D022821:RNA Splice Sites; C085609:SLC26A4 protein, human; D000076988:Sulfate Transporters