biology

Wiedemann–Steiner syndrome

Wiedemann–Steiner syndrome is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Wiedemann–Steiner syndrome rather than just read about it. In short: Wiedemann–Steiner syndrome (WSS) is a rare genetic disorder that causes developmental delay, unusual facial features, short stature, and reduction in muscle tone (hypotonia). The syndrome was originally described in 1989 by Hans-Rudolf Wiedemann.

Key takeaways

Wiedemann–Steiner syndrome belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Wiedemann–Steiner syndrome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Wiedemann–Steiner syndrome from memory before moving on to harder problems.

Reference excerpt

Wiedemann–Steiner syndrome (WSS) is a rare genetic disorder that causes developmental delay, unusual facial features, short stature, and reduction in muscle tone (hypotonia). The syndrome was originally described in 1989 by Hans-Rudolf Wiedemann. The genetic basis for the syndrome was identified by Dr. Wendy D. Jones in 2012. The first case was reported in 1989 by Wiedemann and colleagues which reported a Caucasian boy with pre- and postnatal growth deficiency, psychomotor delay, and a round and flat face, short nose, widely spaced eyes, long philtrum, short palpebral fissures, low-set ears, and high-arched palate. Other findings included an alternating convergent squint, dilatation of the renal calyces, and short and thick limbs. Later decades brought about more finding and descriptions of this disorder.

Signs and symptoms Features described in Wiedemann–Steiner syndrome include:

Short stature Developmental delay Low muscle tone (hypotonia) especially in infancy Characteristic facial features Hairy elbows (hypertrichosis cubiti)

Cause Wiedemann–Steiner syndrome results from mutations in the MLL (also known as KMT2A) gene on the long arm of chromosome 11. The gene encodes a histone-modification enzyme — that is, it helps modify the expression of other genes. The condition is autosomal dominant, meaning that only one abnormal copy of the gene is needed for a person to have the syndrome. The mechanism by which mutations in the MLL gene cause the phenotype of Wiedemann–Steiner syndrome is not yet known.

Screening If Wiedemann–Steiner syndrome is suspected, analysis of the MLL gene can be carried out. Otherwise, it may be diagnosed by whole-exome sequencing or whole genome sequencing. There have also been patients with Wiedemann–Steiner syndrome who were initially mis-diagnosed with Kabuki syndrome.

Treatment There is no specific cure or treatment for Wiedemann–Steiner syndrome. Children with this condition may benefit from a range of supportive treatments such as physiotherapy, speech therapy, supplementary nutrition for poor feeding, and special educational support.

Epidemiology A little over 1000 people have been documented with the condition worldwide. Once thought to have an incidence of 1 in 1,000,000, some research has suggested the incidence may be as high as 1 in 40,000 The approximate number of WSS cases are seemingly low today but offspring of those with WSS have half the chance of having the disorder themselves. There is no current evidence that the life expectancy of individuals with WSS is shortened.

References

7. (Replacement) Sheppard SE, Quintero-Rivera F. Wiedemann-Steiner Syndrome. 2022 May 26. In: Adam MP, Mirzaa GM, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2022. 8. Koenig, R., Meinecke, P., Kuechler, A., Schäfer, D., & Müller, D. (2010). Wiedemann-Steiner syndrome: Three further cases. American Journal of Medical Genetics Part A, 152A(9), 2372–2375. https://doi.org/10.1002/ajmg.a.33587

External links WIEDEMANN–STEINER SYNDROME; WDSTS Wiedemann–Steiner syndrome French web site on Wiedemann-Steiner : syndrome-wiedemann-steiner.fr Wiedemann-Steiner Foundation [1]

Worked examples

Example 1 — a first encounter with Wiedemann–Steiner syndrome

Start with the simplest possible case. Write down what Wiedemann–Steiner syndrome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Wiedemann–Steiner syndrome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Wiedemann–Steiner syndrome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Wiedemann–Steiner syndrome

In research: Wiedemann–Steiner syndrome appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Wiedemann–Steiner syndrome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Wiedemann–Steiner syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genetic syndromes, Rare syndromes, so understanding it makes those chapters shorter.
In everyday life: Look for Wiedemann–Steiner syndrome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Wiedemann–Steiner syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Wiedemann–Steiner syndrome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Wiedemann–Steiner syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Wiedemann–Steiner syndrome in simple terms?

Why does Wiedemann–Steiner syndrome matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Wiedemann–Steiner syndrome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Wiedemann–Steiner syndrome.