Small supernumerary marker chromosomes (sSMCs) have been described from all human chromosomes with different sizes and shapes. However, it is difficult to know the clinical manifestations associated with them, because such knowledge depends on the size, presence of euchromatic material, degree of mosaicism and/or uniparental disomy (UPD).A case report of a familial small supernumerary marker chromosome (sSMC) through a structural and a segregation study is reported.