Expanding the phenotypic spectrum of pathogenic variants in the PRRT2 gene: bilateral papilledema and abducens nerve palsies secondary to pseudotumor cerebri syndrome.

An 8-year-old girl with known pathogenic variant in the PRRT2 gene causing paroxysmal kinesigenic dyskinesia with infantile convulsions presented with bilateral papilledema and abducens nerve palsy, which was subsequently confirmed to be pseudotumor cerebri syndrome (PTCS). She was treated with acetazolamide and recovered baseline vision, with some residual papilledema. PTCS is not confirmed to be associated with pathogenic variants in the PRRT2 gene; however, this case in conjunction with a previously reported case of PTCS and unilateral abducens nerve palsy in a patient with PRRT2 variants, raises the possibility that PTCS is part of the phenotypic spectrum rather than being a coincidental occurrence.

Demyelinating disease of central and peripheral nervous systems associated with a A8344G mutation in tRNALys.

We describe a patient with acute combined demyelinating disease of the central and peripheral nervous systems associated with the A8344G mutation in the mitochondrial tRNA lysine gene. A 7-year-old boy presented with acute onset of palpitations, tinnitus, ataxia, bilateral sixth nerve palsy, and flaccid quadriparesis. Serum creatine kinase and lactate were mildly increased. Electromyography showed demyelinating sensory and motor polyneuropathy. Brain magnetic resonance imaging demonstrated demyelination in the left thalamus and magnetic resonance spectroscopy revealed a lactate peak corresponding to this lesion. Histologic analysis of the muscle showed cytochrome c-oxidase-deficient fibers and ragged red fibers. Respiratory chain analyses revealed deficiencies of complexes I and IV. Molecular genetic analyses of the muscle showed an A8344G (MERRF) mutation in mitochondrial tRNA lysine. To the best of our knowledge, this is the first description of this mutation associated with acute combined demyelinating disease of the central and peripheral nervous systems.

Magnetic resonance imaging of innervational and extraocular muscle abnormalities in Duane-radial ray syndrome.

PURPOSE: The authors used magnetic resonance imaging (MRI) to study extraocular muscles (EOMs) and nerves in Duane-radial ray (Okihiro) syndrome (DRRS) caused by mutations in the transcription factor SALL4. METHODS: The authors examined four male and two female affected members of a pedigree previously reported to cosegregate DRRS and a heterozygous SALL4 mutation. Coronal T1-weighted magnetic resonance images of the orbits and heavily T2-weighted images in the plane of the cranial nerves were obtained in four subjects. MRI findings were correlated with motility examinations and published norms obtained using identical technique. RESULTS: Five of the six subjects with DRRS had radial ray abnormalities including thumb, radial artery, radial bone, and pectoral muscle hypoplasia. Three had bilateral and three had unilateral ocular involvement. Seven eyes had limitation of both abduction and adduction, whereas two had limitations only of abduction. Most affected eyes had lid fissure narrowing and retraction in adduction. Intraorbital and intracranial abducens nerves (CN6) were small to absent, particularly ipsilateral to abduction deficiency. All subjects undergoing MRI had normal intracranial oculomotor nerves (CN3). Optic nerve (ON) cross-section findings were similar to normal. EOMs and pulleys were structurally normal in most subjects. In some affected orbits, a branch of CN3 closely approximated and presumably innervated the LR. CONCLUSIONS: DRRS encompasses a Duane syndrome phenotype, with a variable and asymmetric endophenotype including marked CN6 hypoplasia and probable innervation or coinnervation of the LR by CN3. This endophenotype is more limited than reported in DURS2-linked Duane syndrome (On-line Mendelian Inheritance in Man, OMIM 604356) and CFEOM1 (OMIM 135700), which are clinically similar congenital cranial dysinnervation disorders that also feature CN3 hypoplasia and more widespread EOM abnormalities.

[Retinal vein branch occlusion and palsy of the N. abducens in protein S deficiency]. / Venenastverschluss und Abduzensparese bei Protein-S-Mangel. Eine genealogische Untersuchung.

BACKGROUND: Protein S deficiency, which exists in 0.7% of the population, is a risk factor for retinal vein branch occlusions and is inherited in an autosomal dominant manner. METHODS: A genealogical study was carried out on three generations of one family who exhibited different venous occlusions and subsequent complications. RESULTS: Four members of the family, spanning three generations, suffered from complications of venous thrombosis. In the first generation a great uncle died of complications from a deep leg venous thrombosis. In the second generation, the mother underwent a venous branch thrombosis at the age of 41 with a protein S activity of 18%. Subsequently, a palsy of the N. abducens developed with multiple cerebral lesions (presumably post-thrombotic) in the MRI. Fluorescein angiography showed a typical picture of a venous branch occlusion which had been treated by laser. In the third generation, the 16-year-old daughter developed iliac venous thrombosis and a pulmonary embolism with a protein S activity of 0%. The fluorescein angiography showed distinctively engorged veins. A 28-year-old daughter, with a protein S activity of 16%, remained asymptomatic, although fluorescein angiography demonstrated engorged veins. Protein C activity and APC resistance of all family members were normal. The chromosomal analysis of the family members revealed no morphological aberrations. CONCLUSION: Protein S deficiency increases the risk of congenital thrombosis in young and middle-aged heterozygous individuals.