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Competing Interests: None declared.

Introduction: Charcot-Marie-Tooth (CMT) phenotypes can be distinguished by electrophysiology and genetic analysis but few can be identified by their clinical characteristics. Distinctive phenotypes are useful in identifying affected individuals and providing additional clues about the mechanism of the neuropathy. Cranial neuropathies are uncommon features of CMT, and few reports of familial hemifacial spasm (HFS) and trigeminal neuralgia (TN) have been published., Methods: Sixty-three members of a large CMT 1B kindred were assessed for signs of peripheral neuropathy and cranial neuropathies then tested for the G163R mutation in the myelin protein zero (MPZ) gene., Results: Of 27 individuals with the G163R mutation in MPZ, 10 had HFS or TN. Co-existing HFS and TN were found in 3 of these and 4 had bilateral HFS or TN., Conclusions: This kindred exhibits a distinct CMT phenotype characterized by the development of HFS or TN decades after clinical signs of hereditary neuropathy are manifest. Muscle Nerve, 2019., (© 2019 Wiley Periodicals, Inc.)

Hemifacial spasm is defined as unilateral, involuntary, irregular clonic or tonic movement of muscles innervated by the seventh cranial nerve. Most frequently attributed to vascular loop compression at the root exit zone of the facial nerve, there are many other etiologies of unilateral facial movements that must be considered in the differential diagnosis of hemifacial spasm. The primary purpose of this review is to draw attention to the marked heterogeneity of unilateral facial spasms and to focus on clinical characteristics of mimickers of hemifacial spasm and on atypical presentations of nonvascular cases. In addition to a comprehensive review of the literature on hemifacial spasm, medical records and videos of consecutive patients referred to the Movement Disorders Clinic at Baylor College of Medicine for hemifacial spasm between 2000 and 2010 were reviewed, and videos of illustrative cases were edited. Among 215 patients referred for evaluation of hemifacial spasm, 133 (62%) were classified as primary or idiopathic hemifacial spasm (presumably caused by vascular compression of the ipsilateral facial nerve), and 4 (2%) had hereditary hemifacial spasm. Secondary causes were found in 40 patients (19%) and included Bell's palsy (n=23, 11%), facial nerve injury (n=13, 6%), demyelination (n=2), and brain vascular insults (n=2). There were an additional 38 patients (18%) with hemifacial spasm mimickers classified as psychogenic, tics, dystonia, myoclonus, and hemimasticatory spasm. We concluded that although most cases of hemifacial spasm are idiopathic and probably caused by vascular compression of the facial nerve, other etiologies should be considered in the differential diagnosis, particularly if there are atypical features., (Copyright © 2011 Movement Disorder Society.)

The role of hypertension in the late onset of hemifacial spasm (HFS) is evaluated in a family, spanning four generations. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) revealed a variable anatomical relationship between nervous and vascular structures in the symptomatic cerebello-pontine angle. In one case, showing neurovascular conflict (NVC), microvascular surgical decompression was followed by clinical resolution of HFS. Neuroimaging suggesting NVC was found in all symptomatic patients of the last two generations and in three younger subjects not affected by HFS. As a determinant for the late development of clinical expression is reviewed the role of arterial hypertension, detected few years before HFS appearing in all symptomatic subjects. The distribution of NVC in several members of the same family suggests a genetic susceptibility towards vascular anomaly.

Hemifacial spasm (HFS) has been reported to result from vascular compression of the facial nerve at the root entry zone. The pathogenesis of HFS is not completely understood. Some study groups described that the vascular compression was due to the morphological changes of the vessel such as vertebral artery shifting. In this study, radiological evidence of VA shifting was identified in 26 (59.1%) of 44 patients with 3D-TOF MRA. We hypothesized that a genetic factor might be present for vascular change and tried to find out the role of a genetic factor more susceptible to vascular change causing vascular compression. We examined a single nucleotide polymorphism (SNP) in the genes related to vascular change such as methylenetetrahydrofolate reductase (MTHFR), thymidylate synthase enhancer region (TSER), endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor (VEGF) polymorphisms. 43 HFS patients and 207 healthy controls were genotyped and fasting plasma homocysteine (pHcy) concentrations were measured. The SNPs were genotyped using polymerase chain reaction (PCR) amplification followed by digestion with the restriction enzyme. The pHcy levels were not significantly different between HFS patients and controls. No association was detected between the SNPs in the selected genes and susceptibility to HFS. However, further study will be needed to confirm these findings.

We describe clinical characteristics of 10 patients (five families) with familial hemifacial spasm, with reviews of 13 patients hitherto reported in the literature. There is no clear difference in clinical manifestations between sporadic and familial hemifacial spasms. There is no definite inheritance pattern, but may be autosomal dominant with low penetrance. The ages of onset of familial hemifacial spasm are variable, but occasionally can occur at early years of life. There is a left-side predominance with respect to the affected side of cases with familial hemifacial spasm. Similar to sporadic hemifacial spasm, vascular decompression was effective, suggesting that vascular compression is involved in generating hemifacial spasm even in the familial cases. Familial hemifacial spasm may not be a rare disorder, but may possibly be overlooked. Clarifying the role of genetic susceptibility in pathophysiological mechanisms underlying hemifacial spasm is an important approach toward better understanding of the pathogenesis of cranial rhizopathies.

A patient was evaluated with familial trigeminal neuralgia (TN) and contralateral hemifacial spasm. The mother of the patient, 5 of 10 siblings, and 1 nephew also had TN confirmed by neurologists. The transmission of TN was suggestive of an autosomal dominant inheritance. This family provides additional evidence of a genetic basis for TN in selected cases and also provokes further speculation on a common unifying hypothesis of pathophysiology in cranial rhizopathies.

The authors report the clinical and angiographical findings of two cases of familial hemifacial spasm. This is the fifth description in the literature and presents mother and daughter at the ages of 76 and 51 respectively, in whom the left side was affected. They underwent exams of angioresonance that showed dolichobasilar with left side origin in both patients. The exams also demonstrated postero-inferior cerebellar artery very developed and irregularities in the walls of the vertebral and basilar arteries suggestive of arteriosclerosis in the mother and slightly elongated intracranial vessels in the daughter. Literature review and etiology data of the hemifacial spasm are focused.