Elective mutism and chromosome 18 abnormality

'More than 100 years of silence', elective mutism: a review of the literature

Elective mutism is a rare disorder of communication, where the child speaks fluently in familiar situations, such as home, despite lack of speech in less familiar settings, for example school. A variety of temperamental and behaviour characteristics, co-morbid psychiatric conditions, neurodevelopmental delay and family factors have been associated with the disorder. EM children are described as excessively shy, withdrawn, 'slow to warm up', inhibited, often avoid eye contact, fear social embarrassment and experience significant separation anxiety, on separation from their attachment figures. Their behaviour is often perceived by others as controlling and oppositional. Onset of EM is typically in early childhood years. A number of constitutional and environmental factors have been considered in its onset, progression and response to intervention. Treatment is generally considered to be multimodal, and occurs in a variety of settings, including home and school. Longterm studies suggest that communication difficulties may extend into adulthood. In addition, outcome studies showing a high rate of phobic disorders suggest that EM may be a developmental precursor of adult social phobia. This article reviews the literature on EM, its presentation, aetiology, epidemiology and the various evidence based biopsychosocial treatments.

Cytogenetic abnormalities and fragile-X syndrome in Autism Spectrum Disorder

BACKGROUND

Autism is a behavioral disorder with impaired social interaction, communication, and repetitive and stereotypic behaviors. About 5-10 % of individuals with autism have 'secondary' autism in which an environmental agent, chromosome abnormality, or single gene disorder can be identified. Ninety percent have idiopathic autism and a major gene has not yet been identified. We have assessed the incidence of chromosome abnormalities and Fragile X syndrome in a population of autistic patients referred to our laboratory.

METHODS

Data was analyzed from 433 patients with autistic traits tested using chromosome analysis and/or fluorescence in situ hybridization (FISH) and/or molecular testing for fragile X syndrome by Southern and PCR methods.

RESULTS

The median age was 4 years. Sex ratio was 4.5 males to 1 female [354:79]. A chromosome (cs) abnormality was found in 14/421 [3.33 %] cases. The aberrations were: 4/14 [28%] supernumerary markers; 4/14 [28%] deletions; 1/14 [7%] duplication; 3/14 [21%] inversions; 2/14 [14%] translocations. FISH was performed on 23 cases for reasons other than to characterize a previously identified cytogenetic abnormality. All 23 cases were negative. Fragile-X testing by Southern blots and PCR analysis found 7/316 [2.2 %] with an abnormal result. The mutations detected were: a full mutation (fM) and abnormal methylation in 3 [43 %], mosaic mutations with partial methylation of variable clinical significance in 3 [43%] and a permutation carrier [14%]. The frequency of chromosome and fragile-X abnormalities appears to be within the range in reported surveys (cs 4.8-1.7%, FRAX 2-4%). Limitations of our retrospective study include paucity of behavioral diagnostic information, and a specific clinical criterion for testing.

CONCLUSIONS

Twenty-eight percent of chromosome abnormalities detected in our study were subtle; therefore a high resolution cytogenetic study with a scrutiny of 15q11.2q13, 2q37 and Xp23.3 region should be standard practice when the indication is autism. The higher incidence of mosaic fragile-X mutations with partial methylation compared to FRAXA positive population [50% vs 15-40%] suggests that faint bands and variations in the Southern band pattern may occur in autistic patients.

The Quiet Child: A Literature Review of Selective Mutism

Selective mutism is an unusual but intriguing condition with a reputation for being particularly intractable to intervention. Originally described as 'elective mutism', selective mutism is a heterogeneous disorder associated with a number of individual and family factors including developmental disorders/delay; particular temperamental and personality characteristics; and other co-morbid symptoms and psychiatric disorders. Considered by some in the past as an oppositional disorder, it is the proposal that SM might be a childhood manifestation of an anxiety disorder such as social phobia that has influenced recent developments in the use of behavioural and drug interventions.

Selective mutism and comorbidity with developmental disorder/delay, anxiety disorder, and elimination disorder

OBJECTIVES

To assess the comorbidity of developmental disorder/delay in children with selective mutism (SM) and to assess other comorbid symptoms such as anxiety, enuresis, and encopresis.

METHOD

Subjects with SM and their matched controls were evaluated by a comprehensive assessment of the child and by means of a parental structured diagnostic interview with focus on developmental history. Diagnoses were made according to DSM-IV.

RESULTS

A total of 54 children with SM and 108 control children were evaluated. Of the children with SM, 68.5% met the criteria for a diagnosis reflecting developmental disorder/delay compared with 13.0% in the control group. The criteria for any anxiety diagnosis were met by 74.1% in the SM group and for an elimination disorder by 31.5% versus 7.4% and 9.3%, respectively, in the control group. In the SM group, 46.3% of the children met the criteria for both an anxiety diagnosis and a diagnosis reflecting developmental disorder/delay versus 0.9% in the controls.

CONCLUSIONS

SM is associated with developmental disorder/delay nearly as frequently as with anxiety disorders. The mutism may conceal developmental problems in children with SM. Children with SM often meet diagnostic criteria for both a developmental and an anxiety disorder.

Chromosomal disorders and autism

Many cases of autism appear to be caused by several abnormal genes acting in concert. The literature on chromosomal aberrations in autism is reviewed, with a view to finding potential gene markers for the neuropsychiatric disorder. Most of the chromosomes have been implicated in the genesis of autism. However, aberrations on the long arm of Chromosome 15 and numerical and structural abnormalities of the sex chromosomes have been most frequently reported. These chromosomes appear to hold particular promise in the search for candidate genes.