del (9p) syndrome: proposed behavior phenotype.
Over recent years interest in the study of behavior phenotypes has gained increasing momentum. We present three white female patients, age respectively 9 years 9 months, 14 years 6 months and 18 years at the time of the last observation, seen because of developmental delay/mental retardation, seizures and learning disabilities. Cytogenetic analysis showed a de novo deletion of the short arm of chromosome 9 in all three, with the breakpoint being located at band 9p22. Although several studies have described the somatic phenotype, analytical evaluation of verbal and non-verbal cognitive functions are lacking. Our patients received a detailed neuropsychological and linguistic evaluation that showed a particular behavior profile, in the context of mental retardation of variable degree. On selective tests there was a marked deficit in visuo-praxic and visuo-spatial skills associated with memory disturbance. Visuo-motor integration abilities [VMI; Beery, 1997] and visuo-perceptual and visuo-spatial abilities [Benton line orientation test, 1992] seemed particularly impaired, both in relation to verbal mental age (vocabulary and grammatical production/comprehension) and to some non-verbal competencies [Benton face recognition test, 1992]. The profile shows advanced performances in face recognition. In addition, there is also a dissociation between verbal and visuo-spatial short term memory. This behavior phenotype is similar to that of Williams syndrome (WS) individuals. Our patients also showed some unusual within-domain dissociations regarding linguistic abilities. To better demonstrate similarities and differences between the behavior phenotypes of the del (9p22) syndrome and WS, we studied three IQ-gender-matched WS subjects. The comparison between the cognitive phenotypes of the two syndromes shows similarities in neuropsychological pattern. We hypothesize that there is a gene within the 9p22 region responsible for the neuropsychological profile described here.
Chilosi
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Stella Maris Scientific Research Institute, Division of Child Neurology and Psychiatry, Department of Procreative Medicine and Pediatrics, University of Pisa, Calambrone (Pisa), Italy.
Battaglia
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Brizzolara
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Cipriani
P
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Pfanner
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L
Carey
J C
JC
D000293:Adolescent; D002648:Child; D002872:Chromosome Deletion; D002899:Chromosomes, Human, Pair 9; D005260:Female; D006801:Humans; D007360:Intelligence / Q000235:genetics; D007806:Language Disorders / Q000209:etiology; D010551:Personality / Q000235:genetics; D010641:Phenotype; D018980:Williams Syndrome / Q000235:genetics* / Q000523:psychology