2. Growth patterns of children with special health care needs

2.1 Conditions that alter growth

Chromosomal disorders
Some conditions, which involve abnormalities at the chromosomal level, are associated with growth patterns that differ from those of children without chromosomal abnormalities. It is assumed that these differing growth patterns represent altered growth potential related to the underlying chromosomal abnormality. Examples of conditions related to chromosomal aberrations include Prader-Willi syndrome, Cornelia deLange syndrome, Turner syndrome, and trisomy 21 (also called Down syndrome).

Trisomy 21 will be used to illustrate the challenges in assessing the growth of a child with any chromosomal disorder:

Children with trisomy 21 have an extra chromosome 21 in their cells. They also typically have shorter stature, smaller head circumference and a different pattern of growth, particularly during the first five years of life, than other children (Feucht and Lucas, 2000). Because of these differences, the growth of children with trisomy 21 is not the same as that of the reference children used to develop the CDC growth charts.

Recognition of the differing growth pattern in the child with trisomy 21, and the problem posed by comparing that child's growth to that of average children, led investigators to develop and publish alternative growth charts used with this population (Cronk, et al, 1988). These charts have been used by nutritionists and other clinicians. However, it must be emphasized that there are reasons for which these charts should not be used or not used by themselves. The use of "condition-specific growth charts" is covered in Section 6.

Genetic disorders
For children with genetic disorders, such as a metabolic disorder, there is the potential for altered growth because the affected metabolic pathways are involved in producing energy or building body tissue.