This educational program is created and funded by BioMarin, a company that develops treatments for some of the conditions discussed here. It is meant to support—not replace—conversations with your child's own doctor.
Draft for Review — Not Final
Placeholder imagery is marked "FPO" (For Placement Only). Elements still needing input carry a "⚠ Needs Input" annotation. Copy, claims, imagery, and partner details are pending clinical, community, and MLR/compliance review.
What you're noticing
Start here — you know your child best.
You know your child best.
If something doesn't feel right, you're not imagining it.
Maybe your child looks shorter than other kids their age. Maybe their head seems larger, their arms and legs look short, or they've been dropping to lower lines on the growth chart at checkups. Maybe a doctor said "let's wait and see," but the feeling that something is different hasn't gone away.
Parents are very often the first to notice these things.7 This page is here to help you understand what you may be seeing, and to walk with you through what you can do next—at your own pace.
What you might be noticing
Children grow in their own way and on their own timeline. But a few patterns are worth paying attention to—especially when you see more than one of them together. None of these by itself means something is wrong, and many have ordinary explanations. They are simply signs that are worth a closer look with a knowledgeable professional.
Icons below are a calm, palette-matched SVG set (emoji removed per advocate review; the head-size icon shows head circumference, not a brain). The list of signs, the plain-language wording, and the "not a diagnosis" framing need clinical sign-off from a genetic counselor / pediatric specialist and a community (LPA) language review before launch.Their arms and legs look short compared with their body—sometimes the part nearest the shoulder and hip looks shortest. (Doctors call this disproportionate short stature.)
Their head looks big, or the forehead curves out a little above the eyebrows. The measurement the nurse takes around the head at checkups (head circumference, or macrocephaly when it's large) may be high. A large head can also simply run in the family.
Their growth has slowed, moving from a higher line to lower lines over several visits. (Doctors call this crossing percentiles, or "catch-down" growth.) Some of this is normal in the first couple of years—but a steady downward drift is worth checking.
Late to sit, crawl, or walk. For many children with growth differences these are developmental differences, not delays—the body's proportions, not the mind, set a different timeline.6
Their legs curve outward at the knees (bowing), or their lower back curves in and the belly sticks out. Some bowing is common in toddlers—persistent bowing is worth a look.
Repeated ear infections, crowded teeth, or noisy breathing/snoring can sometimes accompany growth differences and are worth mentioning to your child's doctor.
Seeing some of these doesn't mean your child has a serious condition. Many children with these signs are perfectly healthy. The point is simply this: trust what you're noticing, write it down, and bring it to someone who can help you look more closely.
You are not alone in this. Whatever you're seeing, there's a whole community of families and adults living full lives with these conditions. You can meet that community here whenever you're ready—you don't have to wait for a diagnosis.
Want to jot down some measurements to bring to your doctor?
Try A quick growth check—a private, on-page way to write down your child's height and see it on the U.S. growth chart, so you have something to share at your next appointment. It's educational only, not a diagnosis.
Understanding why
A little background, and what a clear answer can offer.
Why do some children grow this way? A look at the genetics
"Skeletal dysplasia" is an umbrella term for more than 700 rare conditions1 that affect how bone and cartilage grow. These conditions often lead to short arms and legs relative to the body (what doctors call disproportionate short stature), and sometimes a larger head.
At the center of all of this is DNA—the set of instructions the body follows to build itself. Bones rely on specific genes to know how to form cartilage and grow. In a child with a skeletal dysplasia, there is a change (a "variant") in one of these genes that tells the body to grow at a different rate. It is no one's fault—and it says nothing about how loved, capable, or healthy a child will be.
A change in the FGFR3 gene causes achondroplasia, the most common skeletal dysplasia. A different change in the same gene causes hypochondroplasia, which is usually milder.2,5
Genes like COL1A1 or COL2A1 affect the "scaffolding" of bone, which can influence both growth and bone strength.1
These gene changes can be passed down from a parent, but very often they happen for the first time in the child (de novo) around the time of conception—which means they can happen in any family, with no family history at all. In achondroplasia, for example, the great majority of cases are new changes in children born to average-height parents.4,5
“For a while I saw a growth chart and a list of measurements. What I had to remember was that none of it changed who she is—the same funny, stubborn, wonderful kid, whatever a test does or doesn't say.”
If you're ready: what a diagnosis can—and can't—offer
There is no pressure and no rush. Some families want to understand exactly what's going on; others aren't ready yet, and that's okay.
It's also honest to say up front: testing does not always find an answer. Even with today's genome-wide tests, a specific genetic cause is identified in only a minority of children with short stature—more often when there are additional clues such as body-proportion differences, and less often when short stature is the only sign.15,16 Results can also come back uncertain (see things to keep in mind). It helps to think of testing as one step that may bring clarity, not a guarantee.
When testing does point to a cause, that answer can help some families in practical ways:
A few honest things to keep in mind first
- •Testing doesn't always find an answer, and a result can come back uncertain.
- •A test can also turn up unrelated findings you weren't looking for.
- •It's reasonable to have questions about the privacy of genetic information (U.S. law, GINA, offers some protection).
- •A genetic counselor can walk you through all of this before you decide anything. Read the full version below.
1. An answer you can hold onto
Many families spend a long time searching for a name for what they're seeing. When a cause is found, it can bring that search to a close and help you and your care team plan with more confidence.3,9
2. Care that stays ahead of problems
Different dysplasias need different kinds of monitoring. If a specific cause is identified, it can help doctors know what to watch for in your child—for example, regular checks of the area where the skull meets the spine in achondroplasia, which, with monitoring, can meaningfully lower serious risks in infancy.5
3. Access to specific treatments & studies
Some therapies and clinical trials are open only to people with a specific, confirmed genetic diagnosis—such as the FGFR3 change that causes achondroplasia. A confirmed diagnosis is often what makes a child eligible to be considered.3 Eligibility varies from study to study and over time, and this page can't tell you whether any option applies to your child—a clinician or genetic counselor is the person who reviews that with you.
4. Answers for the whole family
When you're ready, a result can help you understand whether a condition was passed down or happened for the first time in your child. A genetic counselor can talk through what it may mean for your family—on your timeline, never as a decision you have to make right now.4
What you can do next
Prepare for a visit and connect with expert help—at your own pace.
Important: this is not a test you order yourself
You can't buy a diagnostic genetic test off a shelf, and you shouldn't have to figure it out alone. Instead, you connect with a licensed genetic counselor or clinician, who talks with you, decides whether testing makes sense, and—if it does—orders the right test and explains the results. In the U.S., a licensed professional is part of the process from start to finish.10 That's there to protect you and your child, so you're never left interpreting a complicated result on your own.
Bring notes to your next appointment
If you've ever felt brushed off, or told to "wait and see" when your gut said otherwise, you're not alone—and your observations matter.8 The most powerful thing you can do is come prepared.
📋 What to note & ask
Print / SaveA short version of the Understanding Your Child's Growth worksheet. There are no wrong answers, and no one knows your child better than you.
- › Height vs. other kids: Is my child much shorter than most children the same age?
- › Growth over time: Has their growth slowed, or clothes and shoes stayed the same size a long time? (Old photos and past heights help.)
- › Body proportions: Do the arms and/or legs look short for the body—and where is it shortest (upper arms & thighs, forearms & shins, or hands & feet)?
- › Trunk, back & arm span: A long body with short limbs (or a short trunk), a curve in the back, or an arm-span that looks shorter than their height?
- › Head, hands & feet: Does the head look a little large for the body; are the hands and feet short and broad?
- › Family & birth history: Is anyone in the family short or living with a bone/growth condition? Both parents' heights? Was my child born small?
- › What I'd like from this visit: Plot growth and estimate adult height, measure body proportions, and—if growth looks uneven—consider X-rays, a referral to genetics or a skeletal dysplasia clinic, a simple test, and support-group info.
Tip: take a photo of your child next to a doorframe or an adult for scale, and bring any growth-chart printouts.
Content adapted from the Understanding Your Child's Growth worksheet PDF. Keep this short version in sync with the full downloadable worksheet; have a genetic counselor / MLR review the final wording.Talk to a genetic counselor, from home
When you're ready, you don't have to travel—or go it alone. In the past, answers often meant a trip to a specialized clinic. Today you can meet a genetic counselor by video. They'll listen, help you decide whether testing is right for your child, and guide you through whatever comes next.
Telehealth options shown are available in the United States.
After you get results—you're not alone
Whatever the results say, the support doesn't stop there. A genetic counselor helps you understand any outcome—a clear diagnosis, an uncertain result, or a test that doesn't find a cause at all. A result that doesn't name a condition is still meaningful, and it doesn't mean the door closes: your counselor and care team stay with you to plan what comes next, at your pace. And the community below is there whether or not a cause is ever found.
You are not the first family to walk this road
Whatever you learn, there is a whole community of families and adults living full lives with these conditions—and they're often the best source of practical wisdom and support. Many families find it helps to connect with others early, not just after a diagnosis.
- • Little People of America (LPA) — community, support, and resources for people of short stature and their families.
- • The MAGIC Foundation — support for children with growth-related conditions.
- • Global Genes — tools to help you advocate and navigate a rare-disease journey.
We use language guided by these communities—for example, "person of short stature" or "little person," and "average height" rather than "normal." If anything here doesn't feel right, that feedback is welcome.
Full copy of this page still needs a formal language/sensitivity review with Little People of America (Jessica Baro) and a genetic counselor, per the advisory meeting. Partner links and the eventual "find a specialist near you" directory are placeholders pending confirmation.Things to keep in mind about testing
Genetic testing is a helpful tool, but it has real limits, and it's important to be honest about them. A test doesn't always give a clear "yes" or "no." Sometimes a result is a "Variant of Uncertain Significance" (VUS)—a change was found, but it isn't yet known whether it affects health. Testing can also turn up unrelated findings you weren't looking for. A diagnosis can be a lot to take in emotionally, and questions about the privacy of genetic information are reasonable—though U.S. law (the Genetic Information Nondiscrimination Act, or GINA) offers some protections. Because your child's situation may also have causes unrelated to a skeletal dysplasia, a genetic counselor can help you weigh whether testing is the right next step—and what it can and can't tell you—before you decide.