Behavioral and Medical Disorders in Children with Down Syndrome in New York

January 31, 2005

Principle Investigator: Susan Hyman, MD
AUCD Institution: Strong Center for Developmental Disabilities
AUCD RTOI #: 2005-1/2-08

Down syndrome (DS) is the most common genetic cause of mental retardation, occurring in 12.5/10,000 births. Autism has a prevalence of up to 34/10,000 with the possible prevalence of 64/10,000 for the entire class of autism spectrum disorders. Case series and one population study found a rate of autism in children with DS of at least 7% (Kent et al, 1999). The rate of autism spectrum disorders in children with mental retardation of varied causes, however, may be as high as 18-30% (de Bildt et al., 2004, la Malfa et al., 2004). It is unknown whether the comorbidity of autism and DS is that of the general population, similar to the rate among other children with mental retardation, or some unique rate for DS.

This study proposes to recruit children 3-13 years of age through the New York Congenital Malformation Registry (NYCMR) with multiple source recruitment through parent support organizations and medical specialists likely to see children with DS. The NYCMR has mandatory reporting of specific congenital disorders including DS. We anticipate that 1145 children living in NY outside of New York City will be sent the initial screening packet with 75% likely to return the completed materials based on prior studies by NYCMR.

Screening tools will include three standard tests: M-CHATE, SCQ and PDD MRS in addition to a medical history questionnaire that will be validated in a pilot study. All children positive on any of the three screens and an equal number of children negative on all three screens will be assessed by ADI-R, Vineland II, and RBS-R by telephone interview. A third level of assessments will be completed using the ADOS and Leiter-R on a subset of children who are ADI-R positive/screen positive and ADI-R negative/screen negative.

Analysis will address prevalence of autism in children with DS and investigate the role of repetitive behaviors, functional skills, and specific medical comorbidities in diagnosis. Identifying ways of differentiating autism from other similar behavioral manifestations in children with DS will aid in counseling families regarding intervention strategies and prognosis.

If an increased rate of autism is identified in children with DS, it will be important to add autism screening to the DS health monitoring protocol, since treatment strategies specific for autism may result in improvement in functional behaviors even in the presence of mental retardation (Smith, 1997). It will also add valuable insight in the neurobiology of autism by clarifying its association with a known genetic condition.