Further delineation of deletion 1p36 syndrome in 60 patients: A recognizable phenotype and common cause of developmental delay and mental retardation

OBJECTIVES. Deletion 1p36 syndrome is a recently delineated disorder, considered to be the most common subtelomeric microdeletion syndrome (1 in 5000 newborns). 1p36.3 deletions account for 0.5% to 1.2% of idiopathic mental retardation; thus, knowledge about the condition is important for pediatricians caring for such patients. Despite 100 reported cases, little is known about its natural history. Our aim was to delineate the natural history of deletion 1p36 and develop complete and accurate information with which to answer families' questions in the clinical setting. PATIENTS AND METHODS. We evaluated 60 patients with the 1p36 deletion syndrome (41 female, 19 male). All underwent physical and neurologic assessments, and most received a psychological evaluation. Standard cytogenetics, fluorescence in situ hybridization of the subtelomeric regions, or array comparative genomic hybridization were used for diagnosis. RESULTS. Fourteen cases were detected by standard cytogenetics, and 46 were detected by fluorescence in situ hybridization of the subtelomeric regions or array comparative genomic hybridization. Occipitofrontal circumference was at ≤2nd centile in 95%, and height and weight ranged between the