Secondary trisomy or mosaic “tetrasomy” 8p

Abstract

We report on two patients with mosaic tetrasomy of 8p[46,XY/47,XY,+i(8p)], a previously unreported cytogenetic anomaly. The first patient had a low percentage of tetrasomic (secondary trisomic) cells in lymphocytes and fibroblasts, an only mildly abnormal phenotype, and a rather benign clinical course. The second patient had a considerably larger percentage of tetrasomic cells in lymphocytes and fibroblasts, and had more severe congenital anomalies that led to his death at 8 months. A characteristic phenotype +i(8p) is suggested but not yet established. The manifestations of these two patients resemble those of mosaic trisomy 8 and mosaic trisomy 8p, with rib and vertebral abnormalities, absent corpus callosum, and enlarged cerebral ventricles.

Complex congenital heart malformations in mosaic tetrasomy 8p: Case report and review of the literature

“…Vertebral/rib anomalies and deep plantar/palmar creases are frequently seen in mosaic tetrasomy 8p and mosaic trisomy 8, but not inv dup 8p. Our patient had some dermatoglyphic anomalies seen in trisomy 8 [Schaumann et al, 1974;Rodewald et al, 1977] and mosaic tetrasomy 8p [Robinow et al, 1989] patients.…”

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We describe a 5-month-old boy with complex congenital heart defects (dTGA, KEY WORDS: mosaic tetrasomy 8p; trisomy 8; congenital heart malformations INTRODUCTION Mosaic tetrasomy 8p has been reported in 10 patients with multiple congenital anomalies and growth and developmental delay [Kristoffersson et al, 1998;Robinow et al, 1989;Roskes et al, 1990;Newton et al, 1993;Tilstra et al, 1993;Fisher et al, 1993;Schrander-Stumpel et al, 1994;Winters et al, 1995]. All patients with tetrasomy 8p have had mosaicism in peripheral blood and, in those investigated (4 cases), in fibroblasts.

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Agenesis of the corpus callosum in mosaic tetrasomy 8p

“…Three patients died within the neonatal period, directly or indirectly as a consequence of complex cardiac defects (Lurie et al, 1995;Winters et al, 1995;López-Pajares et al, 2003). The remaining patient had complete absence of ribs in one hemithorax and succumbed to respiratory failure at 8 months of age (Robinow et al, 1989). It is therefore impossible to comment on mental retardation, motor and speech delay in these five cases.…”

“…In the 14 cases described to date (Kristoffersson et al, 1988;Robinow et al, 1989;Fisher et al, 1993;Newton et al, 1993;Tilstra et al, 1993;SchranderStumpel et al, 1994;Lurie et al, 1995;Winters et al, 1995;Napoleone et al, 1997;Le Bris et al, 2003;López-Pajares et al, 2003;Nucaro et al, 2006), defects in multiple organ systems were present, together with developmental delay and mental retardation. Here we describe a boy with agenesis of the corpus callosum (ACC) and subtle facial dysmorphism as the only identifiable features of mosaic tetrasomy 8p.…”

Mosaicism with a normal cell line and an unbalanced structural rearrangement

“…To our knowledge, only 23 such cases have been reported. They include mosaicism for duplications [Harrod et al, 1980;Cantu and Ruiz, 1986;Serotkin et al, 1988;Blouin et al, 1991;Jewell et al, 1992;Dixon et al, 1993;Gardner et al, 1994], deletions [Wilson and Lin, 1988;Ritter et al, 1990;Patel et al, 1992;D'Alessandro et al, 1992;Finucane et al, 1993;Gordon et al, 1993;Sybert, 1994], insertions [Nielsen et al, 1978], isochromosomes [Robinow et al, 1989;Stanley et al, 1993;Sybert, 1994], and derivative chromosomes [Tsien et al, 1991;Powell et al, 1991;Pelligrino et al, 1995].…”