LAUSR

Mirror movements (MM) refer to a rare phenomenon where simultaneous, identical, contralateral, involuntary movements accompany ipsilateral voluntary movements. In pediatric age group, MM can be isolated in the form of congenital mirror movements, or it can occur in association with other clinical syndromes such as Klippel-Feil syndrome, X-linked Kallmann syndrome, Moebius syndrome, Joubert syndrome, or hemiplegic cerebral palsy. MM can also be “physiological” up to the age of 7 years, after which the maturing brain achieves full control of unimanual voluntary movements. Joubert syndrome (JS) is a rare autosomal recessive disorder, that is characterized by defects in the brainstem and cerebellar vermis, resulting in developmental delay and multiple congenital anomalies syndromes. Individuals with JS have cognitive, behavioral and motor disturbances, and occasionally they can have mirror movements. Herein, we present this rare phenomenon of MM in a patient with JS. A 5-year-old Egyptian girl, product of consanguineous marriage, presented with developmental motor, cognitive and language delay, with poor attention and hyperactivity. Her antenatal and birth history were normal. During infancy, she had transient breathing difficulties, however, she had no hepatic, renal, or retinal abnormalities. Her neurological examination showed mild intellectual disability (IQ score of 55), axial and appendicular ataxia, hypotonia and hyporeflexia. The diagnosis of JS was based on her clinical features and the characteristic radiological appearance of “molar tooth sign” on magnetic resonance imaging (Fig. 1). During clinical assessment, unilateral MM could be noticed, in the form of simultaneous, involuntary, identical movements of the left hand, while the patient was voluntarily moving her right hand, as shown in Video 1. Voluntarily moving the left hand was not associated with MM on the right hand. MM is one of the most peculiar motor dysfunctions observed in humans. It is considered a soft neurologic sign that is rarely seen in clinical practice, and can be easily missed if not specifically looked for. MM are considered pathological if they persisted beyond 7 years of age, and could be congenital or acquired. Our patient had a classic type of JS with brain affection, in the absence of renal, hepatic, ophthalmic, or skeletal abnormalities. Syndromic MM has been reported in individuals with JS, commonly involving the hands, although it may be present in all limbs. They are usually of lesser amplitude than their voluntarily counterpart, and they can be unilateral or bilateral, although one side is generally more affected. Two main pathophysiological mechanisms have been proposed to explain the occurrence of MM with different brain anomalies; (1) MM may arise from the same hemisphere as the voluntary movements through an abnormal ipsilateral projection by an uncrossed fast-conducting corticospinal tracts (CST) that