Instruction for Use: Developmental Milestones in Down Syndrome

Developmental milestones refer to skills that children may acquire over the course of their lifespan. Typically, a skill first emerges and is demonstrated inconsistently until a child masters it, at which point it is considered “achieved.” In the practice of pediatrics, familiarity with typical developmental progression, with the age at which 75% of children typically acquire a skill, and the ability to recognize which children need additional intervention to reach a milestone, are essential competencies. This proves more difficult in a population that almost universally develops differently due to a specific condition, such as those with Down syndrome.Providers who care for individuals with Down syndrome can benefit from understanding the broad range of development that can be observed in this patient population. Descriptions of patient cohorts that include those with co-occurring autism, co-occurring significant visual and hearing impairments, and extensive medical complexity, such as the one examined by Baumer et al,1 ensures inclusivity in this field of inquiry. The result of a more inclusive approach when describing development for children with Down syndrome is higher median ages at which milestones are achieved, a finding that raised concerns among members of our professional organization (the Down Syndrome Medical Interest Group) that are outlined in other comments to this article. This raises the question of how these published milestones should be used clinically.As a physician who directs a clinical program for children with Down syndrome at a large academic institution, I believe that these milestones can be used to reassure a caregiver when their child struggles to achieve a specific milestone, letting them know that they are not alone in their parenting experience, all while offering additional support. The discrepancy between these findings and those published in other, earlier works2–4 will hopefully prompt additional scientific inquiry to understand the reasons for those differences, including elucidating the role that chronic underfunding of developmental disabilities and educational institutions plays in the developmental trajectory of our patients with Down syndrome.It is important to note, however, that these milestones should not be used to delay or deny intervention. Unfortunately, this is already happening. Caregivers have experienced denial of services by insurers and accountable care organizations based on other articles that describe development in Down syndrome5,6; the rationale quoted to families is that “the child’s delays are typical for the condition, as published in the literature, and therefore do not require intervention.” It is imperative that the milestones published by Baumer et al1 not be used to deny services, to set expectations for all children with Down syndrome, or to create a schism in the community between those who are ahead of and those who are behind these developmental timelines. Providers should continue to closely monitor each child’s developmental progress, connect patients with therapeutic support, and promptly identify those whose development is plateauing or regressing. As Dr Bull7 so articulately stated, we must continue to believe in each child’s potential; we must continue to advocate for inclusive education; and, above all, we must accompany caregivers’ journeys with hope, validating their high expectations for their child with Down syndrome.