Increasing cases of 9p syndrome have been reported since the first description in 1970.In the present case, a extra segment of the end of chromosome 9p resulting from a matally inherited translocation t(4;9)(q31;p24) was described in a liveb boy with mental retardation and multiple congenital anomalies. The extra part of chromosome 9p includes segment of the chromosome region 4q31→qter of his mother but deletes a small segment 9p24→pter. To our knowledge, this is the first case described in a liveb child. This paper also includes a review and tabulation of clinical features seen in the 34 reported cases. The new case had most characteristics reported cases besides worried-face, fat and abnormal lower digestion tract, which is a modification and double expansion of the previous summarization on 9p syndrome.