Close genetic linkage between X linked retinitis pigmentosa and a restriction fragment length polymorphism identified by recombinant DNA probe L1.28

Retinitis pigmentosa (RP) is a group of retinal degeneration characterized by progressive visual field loss, night blindness and pigmentary retinopathy. Its prevalence is in the region of 1-2 in 5,000 of the general population, making it one of the commoner causes of blindness in early and middle life. Although 36-48% of RP patients are isolated cases, the remainder show autosomal dominant, autosomal recessive or X-linked modes of inheritance. The X-linked variety ( XLRP ) is found in 14-22% of RP families in the UK. In the present study, X chromosome-specific recombinant DNA probes which can detect restriction fragment length polymorphisms have been used to localize the XLRP gene(s) to a subregion of the X chromosome using linkage analysis. One of the probes, L1.28, has been shown to be closely linked to XLRP in five kindreds, with 95% confidence limits of 0-15 centimorgans (maximum LOD score of 7.89 at a distance of 3 centimorgans). This suggests that the XLRP locus lies on the proximal part of the short arm of the X chromosome. This probe is potentially useful for carrier detection and early diagnosis in about 40% of cases, provided that genetic heterogeneity can be excluded by analysis of further families

Autosomal Dominant Retinitis Pigmentosa: Absence of the Rhodopsin Proline- Histidine Substitution (codon 23) in Pedigrees from Europe

In exon 1 at codon 23 of the rhodopsin gene, a mutation resulting in a proline-to-histidine substitution has previously been observed in approximately 12% of American autosomal dominant retinitis pigmentosa (ADRP) patients. The region around the site of this mutation in the rhodopsin gene has been amplified and analyzed in affected individuals from 91 European ADRP pedigrees. The codon 23 mutation has been found to be absent in all cases, including a large Irish pedigree in which the disease gene has previously been shown to be closely linked to the rhodopsin locus. This indicates the presence of either allelic or nonallelic heterogeneity in ADRP

The Gravity Collective: A Search for the Electromagnetic Counterpart to the Neutron Star-Black Hole Merger GW190814

We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of the LIGO/Virgo gravitational wave (GW) signal from the neutron star-black hole (NSBH) merger GW190814. We searched the GW190814 localization region (19 deg$^{2}$ for the 90th percentile best localization), covering a total of 51 deg$^{2}$ and 94.6% of the two-dimensional localization region. Analyzing the properties of 189 transients that we consider as candidate counterparts to the NSBH merger, including their localizations, discovery times from merger, optical spectra, likely host-galaxy redshifts, and photometric evolution, we conclude that none of these objects are likely to be associated with GW190814. Based on this finding, we consider the likely optical properties of an electromagnetic counterpart to GW190814, including possible kilonovae and short gamma-ray burst afterglows. Using the joint limits from our follow-up imaging, we conclude that a counterpart with an $r$-band decline rate of 0.68 mag day$^{-1}$, similar to the kilonova AT 2017gfo, could peak at an absolute magnitude of at most $-17.8$ mag (50% confidence). Our data are not constraining for ''red'' kilonovae and rule out ''blue'' kilonovae with $M>0.5 M_{\odot}$ (30% confidence). We strongly rule out all known types of short gamma-ray burst afterglows with viewing angles $<$17$^{\circ}$ assuming an initial jet opening angle of $\sim$$5.2^{\circ}$ and explosion energies and circumburst densities similar to afterglows explored in the literature. Finally, we explore the possibility that GW190814 merged in the disk of an active galactic nucleus, of which we find four in the localization region, but we do not find any candidate counterparts among these sources.Comment: 86 pages, 9 figure

Molecular genetic approaches to the analysis of human ophthalmic disease

In this review of the recent literature, the contribution that the new techniques of molecular genetics has made in the analysis and diagnosis of human ophthalmic conditions is presented and discussed. Among the disorders reviewed are X-linked retinitis pigmentosa, Norrie's disease, gyrate atrophy and retinoblastoma, and there are also sections on crystallins and visual pigments

A genetic linkage study of choroideremia

One hundred and twenty-two members of 15 choroideremia families have been used in a genetic linkage study of choroideremia (TCD) using four DNA probes situated on the X chromosome. Linkage was analysed using DNA probes DXS14 (p58-1), DXYS1 (pDP 34), DXS178 (p212) and DXS177 (lambda 2.7). Statistically significant linkage was demonstrated with DXYS1 (theta = 0.00, lod 4.95), in agreement with the findings of Nussbaum et al. (1985). Evidence consistent with loose linkage to TCD was also found with DXS14 (theta = 0.31, lod 0.23), DXS178 (theta = 0.18, lod 1.41) and DXS177 (theta = 0.27, lod 0.20). The results suggest that TCD is located in the region Xq13-q21. Probe DXYS1 is likely to prove useful in the prenatal diagnosis of this condition

Dominant retinitis pigmentosa associated with two rhodopsin gene mutations. Leu-40-Arg and an insertion disrupting the 5'-splice junction of exon 5

OBJECTIVE: To determine the phenotypes of two families in which retinitis pigmentosa cosegregates with a rhodopsin (RHO) gene mutation: a leucine-to-arginine change at codon 40 (Leu-40-Arg) in one family, and a 150-base pair insertion that disrupts the RHO 5'-splice junction of exon 5 in another. PATIENTS: Three affected members of each family. RESULTS: The Leu-40-Arg mutation was associated with the onset of night blindness in the first decade of life. By the fourth decade, severe retinal functional loss was evident on dark-adapted static threshold perimetry, and electroretinographic responses were absent or barely detectable. In contrast, the RHO 150-base pair insertion was associated with the later onset of mild night vision difficulties; in two individuals, mild night vision difficulties were first noticed in the second decade while a third, a 25-year-old woman, was asymptomatic. Dark-adapted static threshold perimetry of this latter individual revealed a "regional" or class 2 pattern of retinal functional loss associated with equal loss of rod and cone electroretinographic responses. CONCLUSION: The RHO Leu-40-Arg mutation causes symptomatic retinal dysfunction by the end of the first decade while the insertion disrupting the 5'-splice junction of RHO exon 5 causes later onset "regional" or class 2 retinal dysfunction