The authors report an observation of partial trisomy 13p13 leads to qter and suggest a clinical map of chromosome 13. Increase of fetal hemoglobin seems to be controlled by region 1 of 13q. Bands q13 q14 and q21 seem to be responsible for inner organ malformations. Lastly, the distal segment q22 leads to qter is responsible for trigonocephaly and limb abnormalities.