Cholesteatoma has a high prevalence in Turner syndrome, highlighting the need for earlier diagnosis and the potential benefits of otoscopy training for paediatricians.

AIM: Girls with Turner syndrome are prone to cholesteatoma, a serious suppurative middle ear disease. We aimed to confirm its high prevalence in Turner syndrome, identify risk factors and suggest possible strategies for earlier detection. METHODS: We reviewed 179 girls with Turner syndrome between 1989 and 2012 to identify cases of cholesteatoma. RESULTS: Seven girls (3.9%) had cholesteatoma (index girls) and each was compared with three age-matched girls without cholesteatoma (comparison girls). All the index girls had either the 45,X or 45,X/46X,i(Xq) karyotypes. Nine ears were initially affected, with three recurrences in two girls. Median age at first cholesteatoma presentation was 11.9 years (range: 7.5-15.2), with otorrhoea for three (range: one to seven) months in all 12 affected ears. Index girls had a significantly higher proportion of previous recurrent acute (p = 0.007) and chronic otitis media (p = 0.008), chronic perforation (p = 0.038) aural polyps (p < 0.0001) and tympanic membrane retraction (p = 0.0001) than comparison girls. CONCLUSION: Cholesteatoma has a high prevalence in Turner syndrome. Risk factors include 45,X and 46,XiXq karyotypes; a history of chronic otitis media, tympanic membrane retraction and persistent otorrhoea; and older age. Earlier recognition of ear disease is needed and otoscopy training for paediatricians caring for Turner syndrome patients may be beneficial.

Nucleotide sequence of the argR gene of Escherichia coli K-12 and isolation of its product, the arginine repressor.

In Escherichia coli, the arginine repressor, the product of the argR gene, in conjunction with L-arginine controls the synthesis of the enzymes of arginine biosynthesis. We describe the nucleotide sequence of the argR gene, including its control region, and show that formation of the repressor is autoregulated. The argR control region contains two promoters, one of which overlaps the operator site and, as with other arg genes, consists of two adjacent palindromic sequences ("ARG boxes"). The arginine repressor protein and an arginine repressor-beta-galactosidase fusion protein were purified, and the amino acid sequence of the N-terminal end of the repressor protein portion of the fusion protein was determined. Antibodies prepared against the fusion protein react with the repressor. The repressor is precipitable by L-arginine, which facilitates its purification. The native repressor is a hexamer with a molecular weight of 98,000; its monomeric subunit has a molecular weight of 16,500. To verify its properties postulated from genetic studies, we show that in the presence of L-arginine, repressor inhibits transcription of argF and binds to the ARG boxes of argF and argR.