Chromosome 22gl1 deletions—An under-recognized cause of idiopathic learning disability?

Murphy, Kevin; Jones, Rowena; Griffiths, E; Thompson, Patrick; Owen, Mike

doi:10.1016/s0920-9964(97)88634-3

Cited by 28 publications

(40 citation statements)

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“…The rate of detecting the deletion however may be higher in adults with a dual diagnosis of schizophrenia and developmental disabilities. One study found 22qDS in 2 (9%) of 22 such subjects (Murphy et al 1998). These preliminary studies indicate that the rate of 22qDS in schizophrenia may be approximately 80 times the estimated general population rate of 22q11.2 deletions (1/4,000) (du Montcel et al 1996).…”

Section: Qds As a Subtype Of Schizophreniamentioning

confidence: 82%

“…Several groups (Bassett et al 1998;Gothelf et al 1997;Murphy et al 1998) have shown that 22qDS may be identified in clinical populations with schizophrenia who are screened for the presence of common syndromal features (see Table 1 for proposed clinical screening criteria). Age at onset, psychotic symptoms, and comorbid symptoms are consistent with those usually found in schizophrenia (Bassett et al 1998;Gothelf et al 1997;Pulver et al 1994).…”

Section: Identifying 22qds In Schizophreniamentioning

confidence: 99%

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22q11 deletion syndrome: a genetic subtype of schizophrenia

Bassett

Chow

1999

Biological Psychiatry

298

229

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Schizophrenia is likely to be caused by several susceptibility genes and may have environmental factors that interact with susceptibility genes and/or nongenetic causes. Recent evidence supports the likelihood that 22q11 Deletion Syndrome (22qDS) represents an identifiable genetic subtype of schizophrenia. 22qDS is an under-recognized genetic syndrome associated with microdeletions on chromosome 22 and a variable expression that often includes mild congenital dysmorphic features, hypernasal speech, and learning difficulties. Initial evidence indicates that a minority of patients with schizophrenia (~2%) may have 22qDS and that prevalence may be somewhat higher in subpopulations with developmental delay. This paper proposes clinical criteria (including facial features, learning disabilities, hypernasal speech, congenital heart defects and other congenital anomalies) to aid in identifying patients with schizophrenia who may have this subtype and outlines features that may increase the index of suspicion for this syndrome. Although no specific causal gene or genes have yet been identified in the deletion region, 22qDS may represent a more homogeneous subtype of schizophrenia. This subtype may serve as a model for neurodevelopmental origins of schizophrenia that could aid in delineating etiologic and pathogenetic mechanisms.

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Section: Qds As a Subtype Of Schizophreniamentioning

confidence: 82%

Section: Identifying 22qds In Schizophreniamentioning

confidence: 99%

22q11 deletion syndrome: a genetic subtype of schizophrenia

Bassett

Chow

1999

Biological Psychiatry

298

229

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“…Notably, for studies of mental retardation in general, schizophrenia status would usually be unknown due to young age of patients. Only one other study investigated dual diagnosis patients for 22q11.2 deletions (Murphy et al, 1998). The trend for recurrent seizures to be more prevalent in the Syndromal group may be consistent with more complex neuropsychiatric expression in individuals with developmental forms of schizophrenia, including those with large, rare CNVs (Bassett et al, in press).…”

Section: Discussionmentioning

confidence: 99%

Clinically detectable copy number variations in a Canadian catchment population of schizophrenia

Bassett

Costain

Fung

et al. 2010

Journal of Psychiatric Research

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Copy number variation (CNV) is a highly topical area of research in schizophrenia, but the clinical relevance is uncertain and the translation to clinical practice is under-studied. There is a paucity of research involving truly community-based samples of schizophrenia and widely available laboratory techniques. Our objective was to determine the prevalence of clinically detectable CNVs in a community sample of schizophrenia, while mimicking typical clinical practice conditions. We used a brief clinical screening protocol for developmental features in adults with schizophrenia for identifying individuals with 22q11.2 deletions and karyotypically detectable chromosomal anomalies in 204 consecutive patients with schizophrenia from a single Canadian catchment area. Twenty-seven (13.2%) subjects met clinical criteria for a possible syndrome, and 26 of these individuals received clinical genetic testing. Five of these, representing 2.5% of the total sample (95% CI: 0.3%-4.6%), including two of ten patients with mental retardation, had clinically detectable anomalies: two 22q11.2 deletions (1.0%), one 47, XYY, and two other novel CNVs -an 8p23.3-p23.1 deletion and a de novo 19p13.3-p13.2 duplication. The results support the utility of screening and genetic testing to identify genetic syndromes in adults with schizophrenia in clinical practice. Identifying large, rare CNVs (particularly 22q11.2 deletions) can lead to significant changes in management, follow-up, and genetic counselling that are helpful to the patient, family, and clinicians.

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“…Many children with 22q11DS, however, have weak pencil grip and poor graphomotor control. 26 Because of early learning disabilities, 27 they are inconsistent in their reading ability. To control for these possible confounders, testers administered each item of the UPSIT to all children.…”

Section: Methodsmentioning

confidence: 99%

Olfactory Disorder in Children With 22q11 Deletion Syndrome

Sobin¹,

Kiley-Brabeck²,

Dale

et al. 2006

Pediatrics

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OBJECTIVE-22q11 deletion syndrome, a common human interstitial deletion syndrome (1:5000), is associated with a heterogeneous physical phenotype, including several factors that markedly increase the risk for olfactory disorder. Despite its potential consequences, pediatric studies of impaired olfaction are rare, and odor detection in children with 22q11 deletion syndrome has not yet been examined. METHODS-TheUniversity of Pennsylvania Smell Identification Test was administered to 62 children, including 39 with 22q11 deletion syndrome and 23 neurotypical control siblings who ranged in age from 5.3 to 14.8 years. Lowered smell detection accuracy among affected children was predicted.RESULTS-Substantially more children with 22q11 deletion syndrome (68%) as compared with neurotypical control subjects (13%) had University of Pennsylvania Smell Identification Test scores ≥2 SDs below the standardization sample mean. Frequency of impairment in younger versus older children did not differ. The score distributions of children with and without velopharyngeal insufficiency did not differ; however, markedly lower score variance among children with velopharyngeal insufficiency suggested its negative impact on olfaction. Posthoc error analyses revealed that affected children had special difficulty detecting smells that are associated with fumes and smoke.CONCLUSIONS-Odor detection failures are ubiquitous among children with 22q11 deletion syndrome and are not associated with developmental delay or performance characteristics of younger affected children. Additional studies are needed to examine further the impact on olfaction of velopharyngeal insufficiency and compromised nasal airway patency. Children with 22q11 deletion syndrome should be evaluated routinely for olfactory disorder. When deficits are identified, caregivers should be warned of potential dangers that are associated with this type of sensory impairment. 22Q11 DELETION SYNDROME (22q11DS), also referred to as DiGeorge or velocardiofacial syndrome, results from a meiotic deletion at the q11.2 site on chromosome 22. It is estimated to occur in at least 1:5000 live births 1 and may be substantially more prevalent. 2 22q11DS results in the loss of ~30 gene copies 3 and a broadly heterogeneous physical phenotype, most typically including structural velopharyngeal anomalies, craniofacial or heart anomalies, and/ or immunologic deficits secondary to thymic irregularities. 4 Interest in the early neurologic and neurocognitive development of children with 22q11DS increased dramatically after reports of higher-than-expected rates of schizophrenia among affected adults. 5Clues regarding the source of neurocognitive differences in 22q11DS may reside in its genetic profile. Among the 30 deleted gene copies are 4 that have a direct and an indirect impact on production and release of glutamate, γ-aminobutyric acid (GABA), and dopa-mine, the 3 neurotransmitters that selectively subserve pathways that link basal ganglia and frontal/ prefrontal cortex 6 and that are impli...

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Chromosome 22gl1 deletions—An under-recognized cause of idiopathic learning disability?

Cited by 28 publications

References 0 publications

22q11 deletion syndrome: a genetic subtype of schizophrenia

22q11 deletion syndrome: a genetic subtype of schizophrenia

Clinically detectable copy number variations in a Canadian catchment population of schizophrenia

Olfactory Disorder in Children With 22q11 Deletion Syndrome

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