translocation is of two types , one which arises by centric fusion of two acrocentric chromosomes called robertsonian translocation and the other is reciprocal translocation , which involves exchange of two chromosome segments ) . two complete acrocentric chromosomes are involved in the centric translocations , and the most common chromosomes found in the robertsonian translocations are chromosome 13 , 14 and 21 . the centric translocation of homologous chromosomes can occur between 13;13 , 14;14 , 15;15 , 21;21 and 22;22 . the commonly seen homologous chromosomal translocations in live - births are for chromosome 13 and 21 . here we are discussing a case with inherited translocation of homologous chromosome 22 with paternal upd . with exceptions , a parent with balanced homologous robertsonian translocations can not have a normal offspring without chromosomal rearrangement . transmission of the balanced homologous chromosomal translocation of chromosome 22 has been reported with no impact of the maternal uniparental disomy ( matupd ) of chromosome 22 . in this study , we report a family with a history of multiple first trimester abortions and the unexpected transmission of the balanced homologous chromosome 22 from father to daughter with the paternal upd . a couple with the history of 7 first trimester miscarriages and a married life of 13 years was referred for genetic counseling . all the routine investigations were found to be normal in their case ; however , neither the couple nor any of the abortus was investigated for the chromosomal abnormality . chromosomal analysis of this couple from peripheral blood culture and trypsin - giemsa banding was done . chromosomal complement of the husband ( m ) was normal 46 , xy ; however , the chromosomal complement of the wife ( s ) was found to be abnormal , i.e. , 45 , xx , t ( 22;22 ) [ figures 1 - 3 ] . karyotype of the daughter(s ) showing the balanced homologous chromosomal translocation t ( 22q;22q ) metaphase showing t ( 22q;22q ) partial karyotype and the ideogram of the daughter ( s ) when the family history was taken and the pedigree [ figure 4 ] was analyzed it was found that she was the only child of her parents , and there was a history of 9 miscarriages to her mother ( m1 ) . thinking that there is a problem with her mother ( m1 ) , her father ( f ) had married with other woman and this step - mother ( m2 ) also had a history of seven first trimester miscarriages without any live birth . pedigree clearly indicated that s had inherited the balanced translocation from her f. she had six paternal uncles and aunts , and none of them had a history of any infertility , miscarriages or fetal deaths . pedigree of the family chromosomal analysis of f showed the same 22/22 translocation [ figure 5 ] . chromosomes of the paternal grand - parents could not be studied as none of them were alive . karyotype of the father(f ) showing the balanced homologous chromosomal translocation t ( 22q;22q ) , with a metaphase and the partial karyotype in this case , it was clear that the women had inherited the balanced homologous translocation of chromosome 22 from her father and her father had not inherited it from his parents . it was also clear that the multiple miscarriages the women had and her mother and her step mother had were because of this chromosomal rearrangement in her and her parent respectively . literature search shows that the person with homologous translocation of chromosome 22 has only two possibilities of chromosomal segregation in his / her gametes ; one is that of nullisomy and the other of disomy of the translocated chromosome . in such a case , the possibilities would be either a conceptus with monosomy or trisomy for chromosome 22 . conceptuses with monosomy or trisomy 22 are not viable and hence lead to miscarriages in the first trimester . in a carrier with balanced homologous chromosomal translocation , it is accepted that all the viable offspring will be abnormal ; and hence the couple is counseled accordingly . however , in the present family , the phenotypically normal daughter had inherited the balanced homologous chromosomal translocation of chromosome 22 from her father . theoretically there are two possible ways that will permit this kind of inheritance of the balanced homologous translocation . one of them is the fertilization of a disomic sperm which is carrying translocated chromosome 22 with a nullisomic oocyte . this is theoretically not acceptable due to the low possibility of formation of nullisomic oocyte especially for chromosome 22 during oogenesis . the other possible way is the disomic sperm fertilizing a normal oocyte resulting into the zygote with trisomy 22 and subsequently leading to trisomic rescue by expelling the free maternal chromosome 22 . the impact of paternal upd for chromosome 22 is not reported in the literature as per our knowledge . in this family , the daughter ( s ) had inherited paternal upd 22 in a translocated form and was phenotypically perfectly normal . we can conclude from this that paternal upd for chromosome 22 also does not impact the phenotype .
rearrangements between homologous chromosomes are extremely rare and manifest mainly as monosomic or trisomic offsprings . 
 there are remarkably few reports of balanced homologous chromosomal translocation t ( 22q ; 22q ) and only two cases of transmission of this balanced homohologous rearrangement from mother to normal daughter are reported . 
 robersonian translocation carriers in non - homologous chromosomes have the ability to have an unaffected child . however , it is not possible to have an unaffected child in cases with robersonian translocations in homologous chromosomes . 
 carriers of homologous chromosome 22 translocations with maternal uniparental disomy do not have any impact on their phenotype . 
 we are presenting a family with a history of multiple first trimester miscarriages and an unexpected inheritance of balanced homologous translocation of chromosome 22 with paternal uniparental disomy . 
 there are no data available regarding the impact of paternal upd 22 on the phenotype . 
 we claim this to be the first report explaining that paternal upd 22 does not impact the phenotype .