biology

Lethal congenital contracture syndrome

Lethal congenital contracture 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 Lethal congenital contracture syndrome rather than just read about it. In short: Lethal congenital contracture syndrome 1 (LCCS1), also called multiple contracture syndrome, Finnish type, is an autosomal recessive genetic disorder characterized by total immobility of a fetus, detectable at around the 13th week of pregnancy. LCCS1 invariably leads to prenatal death before the 32nd gestational week.

Key takeaways

Lethal congenital contracture 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 Lethal congenital contracture syndrome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lethal congenital contracture syndrome from memory before moving on to harder problems.

Reference excerpt

Lethal congenital contracture syndrome 1 (LCCS1), also called multiple contracture syndrome, Finnish type, is an autosomal recessive genetic disorder characterized by total immobility of a fetus, detectable at around the 13th week of pregnancy. LCCS1 invariably leads to prenatal death before the 32nd gestational week. LCCS1 is one of 40 Finnish heritage diseases. It was first described in 1985 and since then, approximately 70 cases have been diagnosed.

Signs and symptoms LCCS1 is characterized by total lack of the movements of the fetus, and is detectable at 13th week of pregnancy. It is accompanied by oedema, small chin, small lungs, crooked joints and occasional skin webs of the neck and elbows. The fetus has characteristic pattern of malpositions recognizable even in severely macerated fetuses with club feet and hyperextension of the knees but the elbows and wrists showing flexion contractures. Neuropathological analysis shows lack of anterior horn motoneurons and severe atrophy of the ventral spinal cord. The skeletal muscles are severely hypoplastic.

Cause The defective gene associated with LCCS1 is the mRNA export mediator GLE1 at chromosome 9q34. In more than 40 families the fetus has been homozygous for A->G substitution (c.432-10A>G) located in intron 3 of GLE1 creating an illegitimate splice acceptor site resulting in nine extra nucleotides in the GLE1 cDNA (GLE1 FinMajor mutation). In one family the fetus has been compound heterozygous for GLE1 FinMajor and R→H substitution in exon 12. A slightly milder phenotype with survival beyond 32nd gestational week also characterized by foetal akinesia, arthrogryposis and anterior horn cell loss (Lethal arthrogryposis with anterior horn cell disease, LAAHD) was also shown to result from mutations in GLE1.

Genetics LCCS1 is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder (GLE1) is located on an autosome (chromosome 9), and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.

Population genetics LCCS1 belongs to Finnish heritage of diseases and cases have been confirmed until now (2009) only in Finland. The prevalence is 1 in 25000 births. The carrier frequency is 1% in whole Finland and 2% in North-Eastern part of Finland where the birthplaces of ancestors of affected individual show clustering.

Mapping Mäkelä-Bengs et al. (1997,1998) performed a genome-wide screening and linkage analysis and assigned the LCCS locus to a defined region of 9q34.

See also Lethal arthrogryposis with anterior horn cell disease

References

External links

Illustrations

Worked examples

Example 1 — a first encounter with Lethal congenital contracture syndrome

Start with the simplest possible case. Write down what Lethal congenital contracture 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 Lethal congenital contracture 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 Lethal congenital contracture 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 Lethal congenital contracture syndrome

In research: Lethal congenital contracture 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 Lethal congenital contracture 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: Lethal congenital contracture syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Autosomal recessive disorders, Finnish heritage disease, Rare diseases, so understanding it makes those chapters shorter.
In everyday life: Look for Lethal congenital contracture 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 Lethal congenital contracture syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lethal congenital contracture 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 Lethal congenital contracture syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lethal congenital contracture syndrome in simple terms?

Why does Lethal congenital contracture 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 Lethal congenital contracture 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 Lethal congenital contracture syndrome.