Familial tremor is described as a form of essential tremor. It is present in more than one individual in a family. It has a genetic component and is inherited in an autosomal dominant pattern. Variants in the LINGO1 (leucine-rich repeat and immunoglobulin domain-containing protein 1) gene have been found to be a predisposing factor for the disease, although the gene responsible for FT has yet to be identified [1].

The clinical features of FT and non-familial ET are almost identical, with the distinction of a negative family history of tremors in sporadic ET. It is further suggested that FT has an earlier age of onset than sporadic ET [2]. Most cases of ET have an onset in middle age, and a minority occur in children and the elderly.

There is no single definition of ET, however, The Movement Disorder Society's Tremor Investigation Group states that in cases of ET, there should not be an underlying etiology [3]. The presentation varies greatly between individuals [4].

The effects of the tremor are most prominent in the upper extremities and rarely affect the lower limbs. Patients may have difficulty carrying out motor tasks such as writing, holding objects and using tools or utensils. In addition, there may be involvement of muscle groups in the head, neck, and eyes. This gives rise to features such as head nodding and vocal tremor.

The amplitude and frequency of tremors vary but may be less prominent at rest. Some patients experience paroxysmal tremors. Although symmetry is a typical feature, a degree of asymmetry is not uncommon. Moreover, tremors are exacerbated by caffeine, heightened emotional states, hunger, certain drugs, and sleep deprivation. In contrast, tremors are alleviated by the ingestion of alcohol (this has been used in the diagnosis of ET) and sleep [5]. The signs are progressive, usually over many years [6]. ET that is diagnosed after the fifth decade of life, tends to progress more rapidly [2].

In a small proportion of reported cases, individuals exhibit neurological symptoms that may include ataxia, dysmetria, intention tremor, and other cerebellar signs [7].

• Anisocoria

  Anisocoria, ataxia, dysarthria, and confusional state were predominant manifestations. Beta activity in the EEG has been described previously with attacks of basilar migraine. [pediatricneurologybriefs.com]

• Tremor

  Familial tremor (FT) is a subtype of essential tremor (ET) that is autosomal dominant. ET and FT are common causes of tremors and can affect individuals both in childhood and adulthood. Familial tremor is described as a form of essential tremor. [symptoma.com]

  Postural tremor resembled essential tremor and responded to the anticonvulsants such as clonazepam, primidone and sodium valproate. Seizures were infrequent. [ncbi.nlm.nih.gov]

  Cf Essential tremor. familial tremor A tremor indistinguishable from essential tremor in its clinical manifestation. Unlike essential tremor, it is inherited as an autosomal dominant trait. [medical-dictionary.thefreedictionary.com]

• Hand Tremor

  Essential tremor is different from Parkinson's disease is three distinct ways: Essential tremor of the hands usually occurs when you use your hands; with Parkinson’s disease, hand tremors occur when your hands are at rest. [houstonmethodist.org]

  Familial neck tremor or hands tremor are benign conditions that even with Western medicine are very hard to treat. [zeel.com]

  See also: Drug-induced tremor Essential tremor Hand tremor Tremor Causes Return to top Tremors occur when there is a problem with the nerves supplying certain muscles. They may affect the whole body or just certain areas, such as your hand. [pacificschoolserver.org]

  Hand tremors also may be reduced with botulinum toxin, but the injections are most effective when only a few muscles are involved in a simple rhythmic motion, and this is not the case with all hand tremors. [hopkinsmedicine.org]

• Action Tremor

  Onset of age is usually in the 60s Intentional Tremor: pastoral, bilateral action tremor of hands, forearms, head, neck, voice. Worsened with emotional stress and intentional movement. Tremor shortly relieved with alcohol. [quizlet.com]

  Postural, or action tremor, is observed when muscles voluntarily contract. This tremor is exhibited with any attempt to keep the limbs or trunk in a particular position, for example to keep the arms outstretched. [emedicinehealth.com]

  Action tremor : Postural tremor occurs when holding a body part, such as the arm, motionless against gravity. Kinetic tremor occurs with voluntary movement, such as writing. [essential-tremor.com]

  Typically, action tremor, which is the hallmark feature of ET, is mildly asymmetric. [frontiersin.org]

  Most people diagnosed with essential tremor have action tremor, which means they shake when they move, and some develop a distinctive nodding or shaking of the head. [health.harvard.edu]

• Tremulousness

  The patients showed either tremulous finger movements or seizures as the initial symptoms between 19 and 30 years of the age without progression. [ncbi.nlm.nih.gov]

  […] voire d autres parties du corps et qui n… … Wikipédia en Français essential tremor — n a common usu. hereditary or familial disorder of movement that is characterized by uncontrolled trembling of the hands and often involuntary nodding of the head and tremulousness [medicine.academic.ru]

  The head can bob, and the voice can take on a tremulous quality because the vocal cords quiver. "Familial" in the "familial tremor" name has real meaning. This kind of tremor has a genetic basis. [articles.sun-sentinel.com]

  Case 1 A young boy aged 12 years attended the outpatient department of tertiary care medical college hospital with the complaint of tremulousness in the legs on standing but the problem resolved on walking or on lying down. [annalsofian.org]

  Other clinical manifestations might be a tremulous voice, a continuous head movement in a vertical "yes, yes" or horizontal "no, no" pattern. The legs are rarely affected. The tremor might be severe enough to result in functional disability. [emedicinehealth.com]

• Vocal Tremor

  This gives rise to features such as head nodding and vocal tremor. The amplitude and frequency of tremors vary but may be less prominent at rest. Some patients experience paroxysmal tremors. [symptoma.com]

  tremor Medication-induced postural tremor Metallic tremor On examination - intention tremor On examination - tremor of tongue On examination - tremor outstretched hands Palatal tremor Physiologic tremor Physiological tremor Postural tremor Progressive [icd9data.com]

  In some people with essential tremor, the tremor may affect the voice (vocal tremor). Essential tremor does not shorten the lifespan. [ghr.nlm.nih.gov]

There is no specific diagnostic test for essential tremor and familial tremor, thus the diagnosis is often clinical. If there are atypical features, clinicians may carry out laboratory and imaging studies to exclude other causes of observed symptoms. These include measuring thyroid, renal and liver function, as well as electrolyte balance. Electromyography is not a routine procedure, although it may be useful.

Imaging techniques employed are computerized tomography (CT) scanning, which should be normal in cases of ET and FT, as well as magnetic resonance imaging (MRI), to rule out central nervous system lesions. Single photon emission CT (SPECT) can be used to accurately diagnose Parkinson's disease, as some cases of ET can be mistaken for the former [8]. Ultrasound has also been used to help delineate causes of tremor[9]. Further conditions to rule out are tremors due to alcohol withdrawal, caffeine, drugs, or anxiety.

1. Tan EK, Teo YY, Prakash KM, et al. LINGO1 variant increases risk of familial essential tremor. Neurology. 2009;73(14):1161–1162.
2. Louis ED, Dogu O. Does age of onset in essential tremor have a bimodal distribution? Data from a tertiary referral setting and a population-based study. Neuroepidemiology. 2007;29(3-4):208-212.
3. Deuschl G, Bain P, Brin M. Consensus statement of the Movement Disorder Society on Tremor. Ad Hoc Scientific Committee. Mov Disord. 1998;13(Suppl 3 M):2–23.
4. Whaley NR, Putzke JD, Baba Y, Wszolek ZK, Uitti RJ. Essential tremor: phenotypic expression in a clinical cohort. Parkinsonism Relat Disord. 2007;13(6):333–339.
5. Voller B, Lines E, McCrossin G, et al. Alcohol challenge and sensitivity to change of the essential tremor rating assessment scale. Mov Disord. 2014;29(4):555–558.
6. Putzke JD, Whaley NR, Baba Y, Wszolek ZK, Uitti RJ. Essential tremor: predictors of disease progression in a clinical cohort. J Neurol Neurosurg Psychiatry. 2006;77(11):1235–1237.
7. Rao AK, Gillman A, Louis ED. Quantitative gait analysis in essential tremor reveals impairments that are maintained into advanced age. Gait Posture. 2011;34(1):65–70.
8. Cuberas-Borrós G, Lorenzo-Bosquet C, Aguadé-Bruix S, et al. Quantitative evaluation of striatal I-123-FP-CIT uptake in essential tremor and parkinsonism. Clin Nucl Med. 2011;36(11):991-996.
9. Kim JS, Oh YS, Kim YI, Koo JS, Yang DW, Lee KS. Transcranial sonography (TCS) in Parkinson's disease (PD) and essential tremor (ET) in relation with putative premotor symptoms of PD. Arch Gerontol Geriatr. 2012;54(3):e436-439.