HLA-DPbeta chain may confer the susceptibility to hepatitis C virus-associated hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a heart muscle disease characterized by hypertrophy and diastolic dysfunction of cardiac ventricles. It is suggested that one possible aetiology of HCM is the hepatitis C virus (HCV) infection, but molecular mechanisms underlying development of HCV-associated HCM (HCV-HCM) remains unknown. Because the human leucocyte antigen (HLA) molecule is involved in the control of progression/suppression of viral infection, extensive HLA allelic diversity may modulate the post-infectious course of HCV and pathogenesis of HCV-HCM. Here we undertook a case-control study with 38 patients with HCV-HCM and 132 unrelated healthy controls to reveal the potential impact of polymorphisms in seven classical and two non-classical HLA genes on the pathogenesis of HCV-HCM. It was found that DPB1*0401 and DPB1*0901 were significantly associated with increased risk to HCV-HCM in dominant model (P < 0.028, OR = 3.94, 95% confidence interval (CI) = 1.19, 13.02) and in recessive model (P < 0.007, OR = 9.85, 95% CI = 1.83, 53.04), respectively. The disparity in the gene-dose effect by two susceptible DPB1 alleles may be attributable to the difference between the susceptible (36 A and 55 A) and resistant (8L, 9F, 11G, 57E and 76M) residue-combination consisting of DPbeta anchor pocket for antigenic peptide-binding. These results implied that the HLA-DP molecules with specificity pocket appropriate for HCV antigen(s) might confer the progressive process of HCM among the HCV-infected individuals.

The haplotype block, NFKBIL1-ATP6V1G2-BAT1-MICB-MICA, within the class III-class I boundary region of the human major histocompatibility complex may control susceptibility to hepatitis C virus-associated dilated cardiomyopathy.

Cardiomyopathy is a heart muscle disease with impaired stretch response that can result in severe heart failure and sudden death. A small proportion of hepatitis C virus (HCV)-infected patients may be predisposed to develop dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). The molecular mechanisms involved in the predisposition remain unknown due in part to the lack of information on their genetic background. Because the human leukocyte antigen (HLA) region has a pivotal role in controlling the susceptibility to HCV-induced liver disease, we hypothesized that particular HLA alleles and/or non-HLA gene alleles within the human major histocompatibility complex (MHC) genomic region might control the predisposition to HCV-associated DCM (HCV-DCM) and/or HCV-associated HCM (HCV-HCM). Here, we present mapping results of the MHC-related susceptibility gene locus for HCV-associated cardiomyopathy by analyzing microsatellite and single nucleotide polymorphism markers. To delineate the susceptibility locus, we genotyped 44 polymorphic markers scattered across the entire MHC region in a total of 59 patients (21 HCV-DCM and 38 HCV-HCM) and 120 controls. We mapped HCV-DCM susceptibility to a non-HLA gene locus spanning from NFKBIL1 to MICA gene loci within the MHC class III-class I boundary region. Our results showed that HCV-DCM was more strongly associated with alleles of the non-HLA genes rather than the HLA genes themselves. In addition, no significant association was found between the MHC markers and HCV-HCM. This marked difference in the MHC-related disease susceptibility for HCV- associated cardiomyopathy strongly suggests that the development of HCV- DCM and HCV-HCM is under the control of different pathogenic mechanisms.

[Medial medullary infarction: report of three patients presented with central vestibular dysfunction without limb and lingual weakness].

The purpose of this article is to draw attention to atypical presentation of medial medullary infarction (MMI). With advanced imaging techniques, small infarctions occurring in the medulla are more easily identified. It is difficult, however, to make a clinical diagnosis of MMI if both hypoglossal nerve palsy and limb weakness are absent, because motor weakness is considered a cardinal manifestation of MMI. We describe here three patients who developed central vestibular dysfunction due to MMI without limb and lingual weakness. Case 1: A 44-year-old, diabetic woman developed vomiting and numbness on her left upper limb. Examination revealed unidirectional horizontal and rotatory nystagmus beating toward the right side. There were no Horner syndrome and hypoglossal nerve palsy. Barré arm and leg signs and limb ataxia were absent. Romberg sign was negative. Hypesthesia was present on her left forearm, hand, and fingers. Thumb-localizing test was normal. Cranial MRI demonstrated an infarction in the right paramedian region of the upper medulla. MR angiography demonstrated irregularity of the basilar and the left vertebral arteries. Case 2: A 69-year-old woman suffered from dizziness and nausea. She showed unidirectional, left-beating horizontal nystagmus. There were no Horner syndrome and hypoglossal nerve palsy, Barré arm and leg signs, and limb ataxia. MRI disclosed an infarction in the left upper medial medulla. Case 3: A 47-year-old man developed vertigo when turning over in bed. He showed left-beating nystagmus without latency, when lying down. Horner syndrome and hypoglossal nerve palsy were absent MRI showed bilateral MMI, with the right lesion being larger than the left. MR angiography demonstrated a stenosis in the distal portion of the left internal carotid artery but not in the vertebral and basilar arteries and their branches. This case represents central positional vertigo. Vestibular syndrome seen in cases 1 and 2 was incomplete and incongruent, suggesting dysfunction of the central vestibular system. There have been only nine cases of MMI with horizontal nystagmus in primary position, including unidirectional horizontorotatory nystagmus. In these cases, horizontal nystagmus beats toward the side of the lesion. In sharp contrast, horizontal nystagmus typically beats away from the lesion side in cases of Wallenberg syndrome, suggesting different underlying mechanism. Unidirectional horizontal and rotatory nystagmus is generally associated with peripheral vestibular dysfunction. There has been no reported case of MMI presenting with vestibular dysfunction preserving motor power. Thus, this "benign" form of MMI might have been misdiagnosed as peripheral vestibular dysfunction before the era of MRI.