Hello and welcome to the Zero to Finals podcast. My name is Tom, and in this episode, I'm going to be talking to you about chromosome disorders.

And if you want to follow along with written notes on this topic, you can follow along at zero definals.com slash chromosome disorders,

or in the genetic section of the zero to finals pediatrics book.

So let's get straight into it.

Chromosome disorders are conditions where there's either a structural abnormality, an abnormal

portion or an abnormal number of chromosomes compared to normal.

Firstly, let's talk about deletion disorders.

Deletion disorders occur where a portion of a chromosome is missing.

These syndromes are very rare and you're unlikely to come across them,

particularly in medical school exams.

One example is creedusha, which is caused by a missing portion of chromosome 5.

Patients have learning, developmental and speech and language difficulties

and a characteristic cat-like cry as infants, which is where the condition gets its name from.

Next, duplication disorders occur where a portion of a chromosome is duplicated.

The chromosome contains twice the normal number of copies of that gene.

One example is Sharke-Marie tooth, which is caused by a duplication of the short arm of chromosome 17.

Patients suffer with sensory and motor neuropathy. tooth, which is caused by a duplication of the short arm of chromosome 17.

Patients suffer with sensory and motor neuropathy, and they have characteristic changes to their feet called Pez-Kavus, which is a high foot arch.

Next, translocation disorders occur where a portion of one chromosome is directly swapped with a portion of another chromosome.

The swap can be balanced, which we call reciprocal translocations, where a portion of one chromosome is swapped with a portion of another.

Alternatively, they can be unbalanced, which we call non-reciprocal translocations, where a

portion of one chromosome leaves the first chromosome and attaches to another chromosome without

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