Mosaic vs. nonmosaic trisomy 9: Report of a liveborn infant evaluated by fluorescence in situ hybridization and review of the literature

Abstract

We report on a newborn infant with multiple congenital anomalies and apparent nonmosaic trisomy 9 in the blood (by conventional cytogenetic studies) who died shortly after birth. Clinical observations at birth and autopsy are compared with phenotypes of mosaic and nonmosaic trisomy 9 cases reported previously. Unlike the initial cytogenetic analysis, fluorescence in situ hybridization (FISH) studies of metaphase and interphase blood cells and skin fibroblasts detected the presence of euploid and trisomy 9 cells. These results suggest that earlier reports of trisomy 9, which relied on conventional chromosome analysis of a few metaphase cells and/or only one tissue type, may not have excluded mosaicism, and that trisomy 9 may be viable only in the mosaic state. © 1996 Wiley‐Liss, Inc.

Two patients with trisomy 9 mosaicism

“… 5 Among mosaic cases, the degree of mosaicism in lymphocytes or fibroblasts does not predict survival or degree of impairment. 5 Another problem is the fact that actual lifetime survival in many patients with trisomy 9 is not known because they were very young at the time of the report. Further accumulation of cases is necessary to understand the natural history and life span in patients with trisomy 9.…”

“…When a routine cytogenetic study does not reveal abnormalities, the analysis should include a larger number of metaphases, another tissue specimen, such as skin fibroblasts, or a fluorescence in situ hybridization study of a larger number of cells from multiple tissues, as Cant et al described. 5 …”

New report of two patients with mosaic trisomy 9 presenting unusual features and longer survival

“…RELATO DE CASOS: O primeiro paciente era um menino de seis anos e cinco meses apresentando peso de 14,5 kg (< P3), altura de 112 cm (P10), perímetro cefálico de 49 cm (P2), proeminência frontal, face triangular e assimétrica, lábios finos, microtia à direita com hélix sobredobrado, mãos pequenas, micropênis (< P10), testículos pequenos e hálux valgo. Seu cariótipo em linfócitos foi mos 47,XY,+9 [4]/46,XY [50]. O estudo citogenético complementar da pele foi normal.…”

Diagnostico Y Manejo Perinatal De Trisomia 9

“…Para la Trisomía 9 parcial o mosaico, se encuentran reportados casos ocasionales desde 1973 (7,8,9). La Trisomía y Tetrasomia 9 están asociadas con síndromes bien establecidos (10,11).…”

“…También se ha descrito otras anormalidades como gliosis moderada, anormalidades del hipocampo, atrofia del cuerpo calloso, ventriculomegalia, hipoplasia del vermis cerebeloso, siringomielia y mielomeningocele (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19).…”