Contributed by Jay S. Raval, MD and Urvashi Surti, PhD
Our patient is a 38-year-old female with a past medical history significant for celiac sprue. She adheres strictly to a gluten-free diet. She is on no medications other than a multivitamin, and she has no family history of illnesses. She had her first child in 2001 (female) via normal spontaneous vaginal delivery and without complications.
However, in 2005, she became pregnant but had an incomplete abortion at 10 weeks gestational age. Perinatal pathology evaluated the products of conception and noted a chorionic sac, degenerated chorionic villi, amnion, partially necrotic inflamed hemorrhagic decidua, gestational endometrium, and clotted blood; additionally, no embryo was seen. Genetic analysis of the products of conception at this time was refused by the patient.
In 2006, the patient again became pregnant and carried her female child to term; the delivery was via normal spontaneous vaginal delivery and medically unremarkable. However, in 2008 she became pregnant but had another incomplete abortion, again at 10 weeks gestational age. Perinatal pathology again evaluated the products of conception and noted degenerated immature chorionic villi, nucleated red blood cells present within fetal vessels, decidua with inflammation and necrosis, and gestational endometrium. This time, however, genetic analysis of the products of conception was authorized by the patient.
PRODUCT OF CONCEPTION KARYOTYPE
In addition to a normal complement of chromosomes for a female fetus, an additional marker chromosome (designated "mar" in the above karyotype) was noted in 20/20 cells examined from the cultured placental villus sample. To potentially identify the marker chromosome, fluorescence in-situ hybridization studies were performed by utilizing probes against chromosomes 14, 15, and 22; these were all negative. Thus, the female karyotype with a marker chromosome was signed out as 47,XX, +mar.ish mar(D14Z1/D22Z1-, D15S10-).
Additionally, peripheral blood chromosome analysis was recommended on both parents in order to determine if the marker chromosome was an inherited marker or a de novo occurrence in this pregnancy. Both parents complied with this request and submitted their peripheral blood for karyotyping. The father was found to have a normal male karyotype (46, XY).
The maternal karyotype revealed a balanced translocation between the q arms of chromosomes 7 and 13 in 20/20 cultured cells. The final karyotype was signed out as 46,XX,t(7;13)(q34;q14.1). See the diagrams below for further demonstration of the involved chromosomal segments in this balanced translocation.