Screening for a Hidden Syndrome
What clue separates a syndrome from a lone , and does Mateo show it?
💡 The syndrome screen is a tool you run on every ; for Mateo it comes back negative, which points toward an .
Prerequisite check
- A pedigree uses standard symbols (squares for males, circles for females, filled for affected, open for unaffected) so any geneticist can read a family at a glance.
- The proband is the person whose case brought the family in, marked with an arrow.
What you will learn
Goal: Students will a by its associated features, use lower- to recognize , and apply that screen to decide that Mateo's cleft looks nonsyndromic (isolated).
- A phenotype is the set of observable features a person has.
- Clefts split into nonsyndromic (no other features, about 70%) and syndromic (packaged with other features, about 30%).
- is the most common , autosomal dominant, with lower- as its hallmark; about 44% of affected people have lip pits alone, with no .
- About 70% of VWS is caused by loss-of-function changes in IRF6.
Model: Two patients side by side, and the Van der Woude fact card
Two babies both have lip and , and you examine each for other features. Baby S (a different patient) has small paramedian pits on the lower lip, webbing behind the knees, and a father with across three affected generations. Baby Mateo has the cleft but no lip pits, no other anomalies, and no confirmed affected relatives. A phenotype is everything you can observe; the clinical question is whether the cleft comes with extra features that travel together. Baby S clearly does. Mateo, on a careful exam, does not.
is the most common syndromic form of . From the research library: VWS is autosomal dominant and accounts for about 2% of all cleft lip and cases. Its hallmark is lower- (small paramedian depressions). About 44% of affected people have lip pits ALONE, with no cleft, which is exactly why mild carriers get missed. Roughly 70% of VWS is caused by loss-of-function changes in a gene called IRF6. So one person in a family might have a full cleft while a parent has only two tiny pits and never knew they carried anything.
Explore (work the model before reading on)
- What features does Baby S have that Mateo does not?
- What fraction of people with have but NO ?
- Baby S has , knee webbing, and three affected generations; Mateo has none of these. Which baby fits the Van der Woude picture, and which looks like a lone ?
- Why is it important to actually CHECK Mateo and his parents for before deciding his is isolated, rather than just assuming?
- If a doctor only looked at clefts and never checked lips for pits, what fraction of VWS carriers would they miss? Then say why that does NOT change Mateo's result.
- In one sentence, what did your team's syndrome screen conclude about Mateo, and what evidence did it rest on?
Guided notes
Two kinds of cleft
- A phenotype is everything we can observe about a person.
- A has no other features and is about ____% of all clefts; a comes with other features and is the remaining ~30%.
The Van der Woude flag
- The hallmark flag is lower-, the sign of .
- VWS is autosomal ______; because 44% of carriers have lip ____ alone with no , a screen must check lips carefully.
Applying the screen to Mateo
- Mateo has no , and neither do his parents; he has no other anomalies on a careful exam.
- So VWS does NOT fit Mateo; his screens as nonsyndromic (isolated), which lines up with about 70% of all clefts being isolated.
Reading the Research
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Track your progress today
Check these off as you work through the lesson, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
- Read the Model and answered the Explore questions.
- Filled in the guided notes in my own words.
- Defined the new vocabulary with an example.
- Built the producible: Write a one-line triage note for Mateo's chart stating whether the cleft screens as syndromic or nonsyndromic and whether the Van der Woude flag (lip pits) is present, then list the specific things you checked to clear him.
- Wrote my Claim, Evidence, and Reasoning exit ticket.
Exit ticket (Claim, Evidence, Reasoning)
- Claim: Mateo's screens as (syndromic / nonsyndromic).
- Evidence: Mateo has ____ and ____ other anomalies, so the hallmark of ____ ____ syndrome is absent.
- Reasoning: When the leading syndromic flag is absent on a careful exam, the is best read as ____, which is the more common kind of cleft anyway.
| Criterion | Proficient | Developing | Beginning |
|---|---|---|---|
| Complete | Every required part of the artifact is present and filled in. | Most parts are present, but one is missing or left blank. | Several parts are missing. |
| Accurate | The science and data are correct and match the evidence. | Mostly correct, with a small factual slip. | Key science or data is wrong. |
| Scientific reasoning (CER) | States a claim, backs it with specific evidence, and explains the reasoning. | Has a claim and evidence, but the reasoning is thin or missing. | Gives an answer with no evidence or reasoning. |
| Professional communication | Clear, organized, and labeled the way a clinician or scientist would write it. | Readable but disorganized or missing labels. | Hard to follow. |
| Submitted | Turned in the right way (Schoology for routine work) and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
- CompleteProficient: Nothing is left blank: the model fills every part of "Write a one-line triage note for Mateo's chart stating whether the cleft screens as syndromic or nonsyndromic and whether the Van der Woude flag (lip pits) is present, then list the specific things you checked to clear him.".
- AccurateProficient: Every number and claim matches the case evidence.
- Scientific reasoning (CER)Proficient: It names a claim, cites the specific evidence, and explains the reasoning, not just the answer.
- Professional communicationProficient: It is organized and labeled like a real chart note.
- SubmittedProficient: It would be turned in on Schoology and confirmed.
Where this leads: careers
What's next: Mateo has no and no other features, so his screens as isolated. But even an must follow some inheritance logic. Does an isolated cleft like Mateo's travel through families the clean way a single dominant gene would?