Prothrombotic gene mutations in patients with sudden sensorineural hearing loss and cardiovascular thrombotic disease.
OBJECTIVE
Impaired cochlear perfusion seems to be an important event in sudden sensorineural hearing loss. Prothrombotic gene mutations have been related to vascular disorders and sudden hearing loss. We assessed the prothrombotic risk in 10 patients with sudden sensorineural hearing loss who had previously experienced cardiovascular events to support its vascular pathogenesis.


METHODS
Ten patients underwent hematologic tests (MTHFR C677T/A1298C, prothrombin G20210A, platelet GlyIIIaA1/A2, and V Leiden G1691A genotyping; fibrinogenemia; cholesterolemia: homocysteinemia; folatemia). The results were compared with those of 100 previously investigated patients with sudden hearing loss alone and those of 200 healthy controls. DNA was isolated from peripheral blood leukocytes, and the gene mutations were investigated by polymerase chain reaction and a LightCycler DNA analyzer.


RESULTS
Two patients had 2 mutant alleles, 6 had 3, and 2 had 4. The mean homocysteine, cholesterol, and fibrinogen levels were above the upper limit of normal; the mean folate levels were slightly above the lower limit of normal. Multiple mutations were more frequent in the patient group than in the previously analyzed patients and healthy controls.


CONCLUSIONS
The association between inherited and acquired prothrombotic factors in patients with sudden sensorineural hearing loss and thrombotic diseases in other sites suggests that a multifactorial mechanism may underlie microvascular cochlear impairment. Hematologic investigation, including MTHFR, prothrombin, platelet, and V Leiden genotyping, may help to detect patients at potential risk of recurrent hearing loss and multiple microvascular diseases, and could be usefully performed in otherwise idiopathic sudden sensorineural hearing loss.
Department of Otorhinolaryngological and Ophthalmological Sciences, University of Milan, Fondazione IRCCS Policlinico, Mangiagalli e Regina Elena, Milan, Italy.
Pasquale
P
Capaccio
Valeria
V
Cuccarini
Francesco
F
Ottaviani
Nicola Stefano
NS
Fracchiolla
Anna
A
Bossi
Lorenzo
L
Pignataro
D000328:Adult; D000368:Aged; D001779:Blood Coagulation Factors / Q000235:genetics*; D002318:Cardiovascular Diseases / Q000150:complications / Q000235:genetics*; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000150:complications / Q000235:genetics; D003639:Hearing Loss, Sudden / Q000150:complications / Q000235:genetics*; D006801:Humans; D039661:Integrin beta3 / Q000235:genetics*; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D009154:Mutation; D012307:Risk Factors
D001779:Blood Coagulation Factors; D039661:Integrin beta3; D042965:Methylenetetrahydrofolate Reductase (NADPH2)