Jugular foramen syndrome, or Vernets syndrome, is characterized by paresis of the glossopharyngeal, vagal, and accessory (with or without the hypoglossal) nerves. Symptoms
Symptoms of this syndrome are consequences of this paresis. As such, an affected patient may show:
dysphonia/hoarseness
soft palate dropping
deviation of the uvula towards the normal side
dysphagia
loss of sensory function from the posterior 1/3 of the tongue (CN IX)
decrease in the parotid gland secretion (CN IX)
loss of gag reflex
sternocleidomastoid and trapezius muscles paresis (CN XI)

Causes
Glomus tumors (most frequently)
Meningiomas
Schwannomas (Acoustic neuroma)
Metastatic tumors located at the cerebellopontine angle
Trauma
Fracture of occipital bone
Infections
Cholesteatoma (very rare)
Obstruction of the jugular foramen due to bone diseases
Nasopharyngeal carcinoma spreading into the parapharyngeal space involving the ninth, tenth, and eleventh cranial nerves

Diagnosis
Gadolinium enhanced mri for vestibular schwannoma
mri and biopsy for nasopharyngeal carcinoma
based on nerve palsies
NCCT for occipital bone fracture


== References ==
Researchers are also investigating whether changes in additional genes, particularly genes on the X chromosome, contribute to the development of signs and symptoms. The degree of heteroplasmy, the percentage of mitochondria that have mutant alleles, may play a role. Patterns of mitochondrial alleles called haplogroup may also affect expression of mutations. History
LHON was first described by the German ophthalmologist Theodor Leber (1840–1917) in 1871. In a paper, Leber described four families in which a number of young men had abrupt loss of vision in both eyes either simultaneously or sequentially. This disease was initially thought to be X-linked but was subsequently shown to be mitochondrial. The nature of the causative mutation was first identified in 1988 by Wallace et al. who discovered the guanine (G) to adenosine (A) mutation at nucleotide position 11778 in nine families. This mutation converts a highly conserved arginine to histidine at codon 340 in the NADH dehydrogenase subunit 4 of complex I of the mitochondrial respiratory chain. The other two mutations known to cause this condition were identified in 1991 (G to A point mutation at nucleotide position 3460) and 1992 (thymidine (T) to cytosine (C) mutation at nucleotide 14484). These three mutations account for over 95% of cases: the 11778 mutation accounts for 50-70% of cases, the 14484 mutation for 10-15% and the 3460 mutation for 8-25%. Research
Human clinical trials are underway at GenSight Biologics (ClinicalTrials.gov # NCT02064569) and the University of Miami (ClinicalTrials.gov # NCT02161380) to examine the safety and efficacy of mitochondrial gene therapy in LHON.