Trisomy 13

Trisomy 13, also known as Patau syndrome, is a relatively common chromosomal abnormality.

Characteristics

Features:

• Midface abnormality - key feature.
  • An extreme example: holoprosencephaly - failure of the forebrain to divide into hemispheres.
• Cardiac abnormalities.
• Aplasia cutis congenita (AKA aplasia cutis) - congenital absence of hair; usu. on the scalp.
• Polydactyly - more than the normal number of digits.
• Horseshoe kidney.
• Rocker bottom feet.

Images:

• Aplasia cutis congenita (WC).
• Polydactyly in trisomy 13 (WC).

A terrible mnemonic

PATAU:

• Polydactyly.
• Aplasia cutis & low hair line.
• Terrible face - midface abnormalities, including cleft left and palate.
• Abnormal heart (cardiac defects).
• Urinary system abnormalities (horseshoe kidney).

See also

• Trisomy 18 (Edwards syndrome).
• Trisomy 21 (Down syndrome).
• Chromosomal anomalies.
• Stillbirth.