Hi, this is Tom, and in this episode I'm going to be going to be going through

chromosome disorders, and you can find notes at 0.0.5.com slash chromosome disorders,

and in the 0 to finals pediatrics book. And you can find flashcards and questions at members.0 tofinals.com.

So let's jump straight in. Chromosome disorders occur where there is either a structural abnormality,

missing or additional chromosomal material, or an abnormal number of chromosomes compared to normal.

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 cre du shat, which is caused by a deletion of part of chromosome 5.

Patients with cre duschat have learning, developmental and speech and language difficulties and a characteristic

cat-like cry as infants.

Duplication disorders. Duplication disorders occur when a portion of a chromosome is duplicated.

The chromosome contains twice the normal number of copies

of that gene. One example is Charcot-Marie tooth, which can be caused by a duplication of a

specific region of chromosome 17. Patients with Charcotomari-ari tooth suffer from sensory and motor neuropathy

and have a characteristic Pez-Kavis or high-arched foot.

Translocation disorders

Translocation disorders occur where a portion of one chromosome is directly swapped with a portion of another chromosome.

The swap can be balanced, which is called reciprocal translocation, in which a portion of one chromosome is directly exchanged for a portion of another.

Alternatively, they can be unbalanced,

which is called non-reciprocal translocation,

in which a portion of one chromosome leaves the first chromosome

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