Non-clinical sciences/Genetics · Chromosomallow yield

Edwards & Patau syndromes

What it means

Edwards (trisomy 18): rocker-bottom feet, micrognathia, overlapping clenched fingers, cardiac/renal defects. Patau (trisomy 13): holoprosencephaly, cleft lip/palate, polydactyly, microphthalmia. Both: severe malformation, very poor prognosis (most die within the first year).

Worked example

Clenched hands with overlapping fingers and rocker-bottom feet → Edwards; midline/holoprosencephaly with polydactyly → Patau.

In the exam

A neonate has overlapping clenched fingers, rocker-bottom feet, micrognathia and a major cardiac defect, with a very poor prognosis.

What settles it

Edwards = 18 (clenched fists, rocker-bottom feet); Patau = 13 (midline defects, polydactyly). Both far more severe than trisomy 21.

Classically confused with

Down syndrome (trisomy 21)

Source: StatPearls