Movement Disorders in 18p Deletion Syndrome: A Case Report and Review of Literature

• Published in: Canadian journal of neurological sciences 2017-07, Vol.44 (4), p.441-443
• Main Authors: Kumar, Niraj, Rizek, Philippe, Jog, Mandar
• Format: Article
• Language: English
• Subjects: Age; Ataxia; Brain research; Case reports; Child development; Chromosome Deletion; Chromosome Disorders - complications; Chromosome Disorders - diagnostic imaging; Chromosomes; Chromosomes, Human, Pair 18; Cognitive ability; Dysarthria; Dystonia; Eye movements; Female; Females; Gait; Genes; Humans; Letters to the Editor; Magnetic Resonance Imaging; Middle Aged; Movement disorders; Movement Disorders - diagnostic imaging; Movement Disorders - etiology; Pharmaceuticals
• ISSN: 0317-1671; 2057-0155
• DOI: 10.1017/cjn.2016.444

Figure 1 Magnetic resonance imaging of the brain shows nonspecific white matter hyperintensities on a T2-weighted image. 18p- syndrome has an incidence of about 1:50,000 live births, with more than 150 cases reported to date.1,2 Females are more commonly affected, with female:male ratio being 3:2.1 Although most cases (approximately 66%-89%) have de novo deletion of 18p, the remainder result from complex translocation, inversion, or direct transmission.1,2 Although uncommon, familial transmission have been described, mostly involving the maternal chromosome.2 Despite approximately 50% of cases having centromeric breakage, 18p- syndrome has a wide clinical heterogeneity with developmental delay, holoprosencephaly, facial dysmorphism, short stature, impaired cognition, and speech and language problems being the major presenting features.1,2 Cognitive impairment, usually mild to moderate, and behavioural abnormalities such as autism and schizophrenia, is more common in centromeric (18p11.1) deletions.1,2 The dysmorphism may not be obvious early in life, thereby causing a delay in recognition.1 Our case was diagnosed at 45 with a de novo deletion involving a 14,520-kB loss of 18p11.32. Brain magnetic resonance imaging of our case showed multifocal nonspecific subcortical T2 white-matter hyperintensities, which has been reported in 50% of cases with 18p- syndrome.2 Myoclonus has been reported in association with dystonia in 18p- syndrome (Table 1).7–9 One case of 18p- syndrome involving GNAL gene was diagnosed with myoclonic jerks alone at the age of 13.2 In addition to the epsilon-sarcoglycan mutation on the chromosome 7q21 (DYT11), a locus on chromosome 18p11.22-31 (DYT15) is implicated in myoclonus dystonia.8 Other movement disorders including chorea,5 vocal tics,10 bradykinesia,4 and tremor7 have been reported in occasional cases, but always in association with dystonia (Table 1). Because the majority of the 18p- syndrome cases are diagnosed early, we suggest a careful observation in the follow-up visits as movement disorders may appear later in life.