L eber hereditary optic neuropathy (LHON) is a form of blindness due to retinal ganglion cell dysfunction (1), caused by mutations in mitochondrial DNA (mtDNA), which affect complex I (NADH-ubiquinone oxidoreductase) of the mitochondrial respiratory chain (2,3). Although rare (estimated prevalence of 1 in 27,000-45,000), it affects all ages and gender, causing rapid and severe, bilateral (usually sequential), painless loss of central vision (4-7). Spon

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The RDS-peripherin gene encodes a photoreceptor-specific protein that is localized in the outer segment disc membranes of both rods and cones. We screened a Spanish family with central areolar choroidal dystrophy for mutations in candidate genes. A base substitution was identified in the RDS-peripherin gene of one patient and DNA sequencing revealed a C-to-T transition in codon 172, arginine being substituted by tryptophan. The mutation was also detected in two asymptomatic family members who showed irregular pigmentation in the retinal pigment epithelium (RPE). The phenotype is similar to other macular dystrophies caused by mutation in the RDS-peripherin gene.

The onset of Leber hereditary optic neuropathy is relatively rare in childhood and, interestingly, the rate of spontaneous visual recovery is very high in this group of patients. Here, we report a child harboring a rare pathological mitochondrial DNA mutation, present in heteroplasmy, associated with the disease. A patient follow-up showed a rapid recovery of the vision accompanied by a decrease of the percentage of mutated mtDNA. A retrospective study on the age of recovery of all childhood-onset Leber hereditary optic neuropathy patients reported in the literature suggested that this process was probably related with pubertal changes.

Horner's syndrome is characterized by a classic triad of ipsilateral pupillary miosis, partial eyelid ptosis, and facial anhydrosis. This case study reports a 7-year-old boy with right miosis, mild blepharoptosis, and iris hypopigmentation detected in a routine pediatric follow-up without ipsilateral facial anhydrosis, flushing, or pain. There was no history of birth trauma and test with cocaine provoked no response of the right pupil, suggesting right Horner's syndrome. Mediastinal tumor was ruled out and brain magnetic resonance imaging incidentally showed absence of flow in the right internal carotid artery. Subsequent magnetic resonance angiography demonstrated agenesis of the right internal carotid artery without other vascular-associated malformations. The final diagnosis was right, congenital Horner's syndrome due to ipsilateral internal carotid agenesis. We describe in detail the radiological findings and pathophysiological mechanisms of this unusual association.