Phenotypic high myopia in X-linked retinitis pigmentosa secondary to a novel mutation in the RPGR gene.

BACKGROUND: Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous disease causing progressive degeneration of retinal photoreceptor cells. The most severe form of this disease is X-linked RP (XLRP), in which photoreceptor degeneration begins in early childhood and complete blindness often occurs by the fourth decade of life. Two genes commonly associated with XLRP have been previously identified. MATERIAL AND METHODS: One Spanish family with confirmed XLRP was studied for mutations using direct sequencing. A genotype-phenotype correlation with pathologic myopia (PM) is detailed. RESULTS: A new pathogenic mutation in the third exon of the RP GTPase regulator (RPGR) was identified: a variant c212C>G (pSER71*). This mutation appears as a hemizygous variant in the male proband with RP, and as heterozygous variant in the females of this pedigree who invariably exhibit symmetrical PM in both eyes. CONCLUSION: A complete family history allowed determination of the inheritance pattern providing genetic counseling for patients and their families. The geno-phenotypic attributes of this heterozygosity suggest a correlation between RP and PM. This novel mutation would expand the mutation spectrum of RP2 and RPGR, and help to study molecular pathogenesis of RP.

Isolated Fourth Nerve Palsy in Tuberculous Meningitis.

Tuberculous meningitis is a type of subacute meningitis and like other intracranial processes can compromise ocular motor nerves, causing palsies. Trochlear nerve is an unusual isolated manifestation in this type of pathology. The authors report a 5-year-old boy presented in their clinic with a trochlear nerve palsy as unique neurological manifestation of tuberculous meningitis. Treatment with complete anti-tuberculous therapy and botulinum A toxin was needed to get the complete resolution of the nerve palsy. In tuberculous meningitis, the presence of high protein levels and higher number of cells in cerebrospinal fluid is associated with cranial nerve involvement. Usually cranial nerve palsies occur in combination. VI cranial nerve alone or a combined disorder of VI and III cranial nerves are the palsies most frequently presented. Much less common is an isolated disorder of IV cranial nerve in the course of meningitis. The length of full treatment with anti-tuberculous therapy in this case was of 1 year. The persistence of palsy 1 month after the beginning of the symptoms indicated the possibility of a botulinum toxin injection with complete resolution of the process without disability, ocular motility has remained normal on follow-up.