In honor of this special day, I'm going to make a little post on sewing for children with Ds. Because all of the things associated with Ds are in the general population, I think it will help a lot of people trying to sew for their kids with unique shapes.
First, I made a chart in inches of what an average child that patterns are made for. This is actually a cross between the Ottobre sheet and the Big 4 (Simplicity, McCalls, Vogue, and Butterick) according to randomly chosen pattern sheets. I used the sizes for girls, but if you have a boy, the difference will only show starting around puberty (unlike ready-to-wear). I believe the big fitting issues that have to do with Down syndrome are the length of the sleeve, the length of the inseam and outseam, and the distance from neck to edge of shoulder. To begin to find what your particular child's fitting issues are, I would take each of the measurements on the charts. When you compare to the chart, you will find where your child has fitting issues.
|Height||Chest||Waist||Hip||Sleeve||Back Waist||Outseam||Shoulder||Big 4|
|19 3/4||17||18||20||7||0||12 1/4||0||Premie|
|22||17 2/4||18 2/4||20 2/4||7 3/4||0||13 2/4||0|
|24 2/4||18||19||20 3/4||8 3/4||0||14 2/4||0||Newborn|
|26 3/4||18 3/4||19 1/4||21 1/4||9 2/4||0||16 1/4||0||Small (1/2)|
|29 1/4||19 1/4||19 3/4||21 3/4||10 1/4||0||17 1/4||0||Medium|
|31 2/4||20||20||22||11||0||18 2/4||0||Large (1)|
|33 3/4||20 2/4||20 2/4||22 2/4||11 3/4||0||20||0||2|
|36 1/4||21 1/4||20 3/4||22 3/4||12 2/4||8 3/4||21 1/4||3 1/4|
|38 2/4||22||21 1/4||23 2/4||13 2/4||9 2/4||22 3/4||3 1/4||3|
|41||22 3/4||21 3/4||24 2/4||14 1/4||9 3/4||24 2/4||3 2/4||4|
|43 1/4||23 2/4||22||25 1/4||15||10 2/4||26||3 2/4||5|
|45 3/4||24 2/4||22 2/4||26||15 3/4||11||27 2/4||3 3/4|
|48||25 1/4||22 3/4||26 3/4||16 2/4||11 2/4||29 1/4||4||6|
|50 2/4||26||23 1/4||27 2/4||17 1/4||12 1/4||30 3/4||4||7|
|52 3/4||26 3/4||24||28 1/4||18||12 3/4||32 1/4||4 1/4||8|
|55||28||24 3/4||29 2/4||19||13 2/4||33 3/4||4 2/4||10|
|57 2/4||28 3/4||25 1/4||31||19 3/4||14||35 2/4||4 2/4||12|
|59 3/4||30||26||32 1/4||20 2/4||14 2/4||36 3/4||4 3/4||14|
|62 1/4||31||26 3/4||33 2/4||21 2/4||15 1/4||38 1/4||5|
|64 2/4||32 1/4||27 2/4||34 3/4||22 2/4||15 3/4||39 2/4||5|
|67||33 2/4||28 1/4||35 3/4||23 2/4||16 1/4||41 1/4||5 1/4|
Patterns for the Big 4 have a lot of ease for movement and growth. This means that most of the clothing made from these patterns are going to be fairly baggy. This is important because you do not want to choose a larger size for growth, because it will be gigantic on them. I trace all my patterns for my girls (though I wouldn't have to for Darth Baby as she fits the mold fairly well).
For tracing the patterns I use the widest medical table paper. For dresses and tops, the first thing that I trace is the shoulder area for the size for the shoulder area. On children with Ds, it is my belief that this is going to be a much smaller pattern size than for height, even if your child is a heavier child than average. The key here is to make sure that the head opening is traced for the larger size and the end of the shoulder and the top of the armhole is for the smaller size. It is also important to extend any openings for the neck area as a smaller size will still need to open up for their head. So if it asks for a 7 inch zipper, you may want to choose a 9 inch or if it uses buttons, you might want to add an extra one, you will also have to extend any areas associated with that opening. I would do this after I had the rest of the pattern traced and then make those adjustments to the tracing.
To make adding sleeves and using their adjustment easy, trace the armhole for the size that best fits your child around the waist. After the shoulder and armhole have been traced, move the tracing so that the marks you have made now line up with the larger size that you are using at the shoulders. Then start tracing from the armhole to the bottom of the pattern. For the sleeve length, only feel the need to make changes for long sleeves and simply shorten the sleeve at the arm opening by the difference between your child's arm and that of the ideal. If there is more to the pattern than a simple hem, make the changes just above what the opening would require. For those sleeves that are graded, make as smooth a line from the opening to your change, or you could even make a straight line with a ruler.
For pants and skirts, choose the size on the waist measurement and shorten the length of the pant to fit your child. For overly thin children, this may not work. For the bear cub, who is quite thin, I choose the size based on height, and then adjust both the length and the width. This is because if I make the size for her waist, then the pants will not come up completely to her waist. I hope this helps anyone sewing for their special someone. If you need more details or maybe some pictures to help, let me know and I'll take some when I adjust a future pattern.