Trisomy 8 mosaicism a controversial prenatal diagnosis

Trisomy 8 mosaicism in the placenta: A Danish cohort study of 37 cases and a literature review

“…This is also demonstrated in Table S2, where eight out of 12 cases of T8M, not detected prenatally prior to the analyses of fetal tissue, had a previous result of AF showing a normal karyotype: again, a false negative result. Similar findings have previously been published 10,24‐27,37,38,46,47 …”

“…Similar findings have previously been published. 10,[24][25][26][27]37,38,46,47 In the published literature (both the cases presented in Table 1 and in Tables S1 and S2) [68][69][70][71][72][73][74][75][76][77][78][79][80] , 80 cases included reports of the phenotypic outcome. However, many of the cases were not followed up postnatally in terms of growth and neurologic development.…”

“…Only 19 cases had a follow-up period of one year or more. 10,[25][26][27][28][29] While many of the traits in the T8M syndrome (Warkany syndrome) are visible at birth (deep palmar and plantar creases, facial dysmorphisms, contractures of fingers and toes and spinal deformities 10,11 ), some can only be recognized by extensive examination of internal organs (agenesis of the corpus callosum, cardiac and renal malformations 26 ) and some can only be recognized as the child develops (intellectual disability, cognitive impairment and cancer 8,[10][11][12][13] ). More than half of the cases in the literature including phenotypic outcome, reported a normal phenotype at birth.…”

“…Cases of trisomy 8 mosaicism with analysis of amniotic fluid and fetal blood after detection in CVS Of the 109 published cases, 80 reported phenotypic outcomes; of these, 58 were reported as having a normal phenotype. Nineteen cases had a follow-up period of >1 year10,[25][26][27][28][29] ; the rest only reported the phenotype at the time of birth. The 22 abnormal outcomes reported included heart malformations (atrial and ventricular septal defects), intrauterine growth retardation, club foot, clinodactyly, renal malformations, facial dysmorphisms, hernias, meningomyelocele, agenesis of the corpus callosum, deep palmar and plantar creases and pulmonary hypertension.…”

First trimester screening for other trisomies than trisomy 21, 18, and 13

“…Other rare fetal trisomies, like T9, T8, and T20, are usually lethal and result in early miscarriage. However, placental mosaicism for one of these three aneuploidies displays variable phenotypes from severe fetal anomalies to normal fetuses of normal birth weight . In order to provide the best counseling to the pregnant couple, it is of value to detect these cases of rare fetal aneuploidies as early in the pregnancy as possible.…”