What are the symptoms? CLS is characterised by a number of features some of which, to a greater or lesser degree of severity, are present in affected individuals, with females likely to be less severely affected. Manifestations include: significant learning delay (see entry Learning Disability)mild-to-moderate restricted growth (see entry Restricted Growth)speech problems (see entry Speech and Language Impairment)facial features that may include abnormally prominent brow, unusually thick eyebrows, down slanting palpebral fissures (eyelid folds), hypertelorism (widely-spaced eyes), a broad nose, protruding (nares) nostrils, maxillary hypoplasia (an underdeveloped upper jaw bone) and large earsprogressive coarsening of the facial features‘puffy’ hands and feet with tapering digitskyphoscoliosis (backward and lateral curvature of the spine; see entry Scoliosis)stimulus-induced drop attacks (episodes of interruption to the cerebral (brain) blood flow affecting the balance and causing the individual to fall) affecting ten to 20 per cent of children and adolescents. Although no clear pattern of behavioural or psychological features relating to CLS has been established, people with the syndrome seem to have a higher incidence of psychiatric difficulties. What are the causes? CLS is caused by a defective gene, RSK2, on the X chromosome (Xp22.2-p22.1). It is not clear how mutations (changes) in the DNA structure of the gene lead to the manifestations of the disorder. How is it diagnosed? CLS is diagnosed when Learning Disability is observed together with characteristic craniofacial and hand abnormalities. Some affected individuals have unusual brief collapses or ‘drop attacks’ that may be precipitated by emotional or auditory stimuli, for example, sudden loud noises. Molecular genetic testing of the RSK2 gene can confirm the diagnosis. However, mutations are not found in all cases. Sometimes changes in the RSK2 gene causes learning difficulties without any outward, physical signs of CLS. How is it treated? Treatment of CLS is symptomatic (designed to treat the displayed symptoms in an individual), including physiotherapy and speech therapy to improve the affected individual’s abilities. The drop attacks may get better with medication prescribed by a neurologist who is aware of this complication of CLS. Inheritance patterns and prenatal diagnosis Inheritance patternsCLS is X-linked dominant. Carrier females are at risk of some learning disability and the physical features of the syndrome. Prenatal diagnosisThis is possible where it is already known that there is an affected family member in whom a mutation has been identified. Alternatively, linkage analysis (a technique that traces patterns of heredity in at risk families, in an attempt to locate a disease-causing gene mutation by identifying traits that are co-inherited with it) can be used. Is there support? Information and support in the UK for Coffin-Lowry syndrome is provided by Climb (see entry Inherited Metabolic diseases).