Phenotypic expression of Bardet–Biedl syndrome in patients homozygous for the common M390R mutation in the BBS1 gene

Abstract

The observed phenotype matches very closely that reported in patients by Azari et al. (IOVS 2006) and in the Bbs1-M390R knock-in mouse model, and expands it to the characterization of important ERG response characteristics that provide insight in the pathogenesis of retinopathy in these patients. Our findings confirm the consistent pathogenicity of the BBS1 M390R mutation.

Comprehensive molecular diagnosis of 179 Leber congenital amaurosis and juvenile retinitis pigmentosa patients by targeted next generation sequencing

“…Mutations in these genes were known to cause syndromes that are characterised by visual impairment and other systemic features 70–72. It was also reported in some cases that these genes were associated with ‘LCA-like’ or ‘RP-like’ phenotypes without defects in other organs 60 62 73. In our study, revisiting these patients confirmed their severe retinal degenerations without other syndromic features (see online supplementary table S1).…”

Knockdown of the BBS10 Gene Product Affects Apical Targeting of AQP2 in Renal Cells: A Possible Explanation for the Polyuria Associated with Bardet-Biedl Syndrome

“…This is not surprising since this mutation is recurrent and accounts for approximately 27% of all cases of BBS [29]. It is usually associated with a very mild ocular phenotype and often correlates with very mild or no renal disease, in BBS patients [29].…”

Abnormal cone ERGs in a family with congenital nystagmus and photophobia harboring a p.X423Lfs mutation in the PAX6 gene

“…The equipment is mounted on a portable cart and features a Ganzfeld dome attached to the cart with a moving arm that allows for positioning over the head of a recumbent patient on the OR bed. Testing in the OR was performed under dark-adapted (DA) conditions, following an abbreviated 20-min DA time, after which all skin (gold cups) and corneal (ERG Jet) electrodes were applied according to standard procedures under dim lighting conditions [1][2][3]. All OR instruments and monitors were equipped with red screens to minimize their impact on the ERG recording and directed away from the recording table.…”

“…The face of the recumbent child was covered with the Ganzfeld dome and monitored via a built-in infrared camera. All procedures and flash intensities were in line with the International Society for Clinical Electrophysiology of Vision standard for clinical ERGs [2] and matched the previously reported ones for our laboratory [1,3,4]. All responses were averaged, collecting a minimum of 10 responses and as many as 90 (flicker) under all testing conditions.…”

“…All responses were averaged, collecting a minimum of 10 responses and as many as 90 (flicker) under all testing conditions. Stimulus frequencies were 0.35 Hz for all DA tests, 1.4 Hz for the light-adapted (LA) cone ERG, and 29 Hz for the LA flicker ERG, as previously reported [3]. ERGs were recorded on the father of the proband with the same methods, except that testing on him was performed in a standard clinical setting without the aid of any form of anesthesia or sedation.…”