DEVELOPMENTAL MILESTONES
COMPARISONS OF MOSAIC & NON-MOSAIC DOWN SYNDROME
In the 1996 mosaic Down syndrome research publication of the Medical College of Virginia (MCV), Virginia Commonwealth University, researchers matched 28 pairs of individuals with mosaic and non-mosaic Down syndrome. This match was to compare the similarities and differences of mosaic and non-mosaic Down syndrome. With the exception of speech, there was a trend toward individuals with mosaic DS reaching the milestone evaluated at an earlier age than those with non-mosaic Down syndrome. However, a clear difference (identified by statistical testing) was apparent only for crawling and walking.
| Milestone | Mosaic Down syndrome | Non-Mosaic DS |
| Rolled Over | 4.65 months | 5.06 months |
| Sat Alone | 8.59 months | 9.44 months |
| *Crawled | 11.24 months | 13.89 months |
| *Walked Alone | 20.54 months | 24.33 months |
Spoke first word other than mama/dada | 19.13 months | 17.94 months |
| Drank from cup alone | 17.00 months | 19.64 months |
| Walked up stairs | 24.77 months | 34.20 months |
* = statistical difference between mosaic and non-mosaic groups
IMDSA recognizes that this is an average age and in no way an absolute guideline for when individuals with mosaic Down syndrome will meet their milestones .
COMPARISONS OF CHILDREN W/MOSAIC DOWN SYNDROME AND SIBLINGS
In another part of this study 45 individuals ranging in the age of 4 months to 33 yrs were compared to their siblings when asked when each group met developmental milestones.
| In Months | Children w/MDS | Siblings | ||
| Milestone | ^Avg | Range | ^Avg | Range |
| Rolled Over | 4.5 | 1-12 | 3.5 | 1-6 |
| *Sat Alone | 8.5 | 4-15 | 6 | 4-8.5 |
| *Crawled | 11 | 6-23 | 7 | 3-11 |
**Spoke first word | 18 | 6-60 | 11 | 5-18 |
*Walked | 20 | 9-30 | 11 | 8-16 |
| *Walked up stairs | 25 | 9-48 | 17 | 10-24 |
| *Toilet Trained | 44 | 20-72+ | 27 | 17-48 |
| *Self Dressed | 49 | 32-96 | 36 | 24-60 |
* = statistical difference between children with mosaicism and their siblings
** = first word other than mama or dada
* Age in chart is counted by months
^ - AVG = Average
IMDSA recognizes that there is a wide age range in developmental milestones for children with mosaic Down syndrome and in most cases, a significant developmental delay when compared to their siblings according to this research conducted by MCV.