Unusual Clinical Presentation of the 3q29 Microdeletion Syndrome: Autism and Psychotic Symptoms. F. Quintero-Rivera1, J. A. Martinez-Agosto2 1) Pathology & Lab Medicine, David Geffen Sch Med UCLA, Los Angeles, CA; 2) Department of Human Genetics and Division of Medical Genetics, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, CA.

   The screening of individuals with minimal dysmorphic features and mental retardation as the predominant feature has resulted in the delineation of several new microdeletion syndromes. Interstitial deletions of 3q29 have been recently described as one of these new syndromes. The clinical phenotype is variable despite an almost identical deletion size. Here, we report on a new individual to further expand the clinical presentation of this rare disorder and compare with previous reports to further define the phenotype. The proband is a 10 year-old female with a history of autism and schizophrenia versus bipolar disorder presenting with increasing suicidal ideation, and dysmorphic features including: epicanthal folds, a broad nasal bridge with a prominent metopic suture and micrognathia, asymmetric face with the right face and lips drooping, and myopathic face, almond-shaped eyes, mandibular hypoplasia, and tapered fingers. SNP array CGH detected a 1.629 Kb de novo chromosome 3q29 interstitial microdeletion, arr cgh 3q29(197194059-198823098)x1. These findings were confirmed by standard chromosome analysis (550- band resolution) and FISH with the 3p/3q subtelomere Vysis probe, 46,XX,del(3)(q29).ish 3p(TELx2),3q(TELx1). This 1.6 Mb deletion encompasses 5 known genes (PCYT1A, PAK2, MFI2, DLG1, BDH), and 17 uncharacterized transcripts. Our patient expands the phenotypic features of 3q29 deletion syndrome. The unusual clinical presentation reflects a general trend towards the classification of mental retardation syndromes associated with fine chromosomal abnormalities on the basis of similar molecular abnormalities, and not on grouping of clinical dysmorphology features alone.