Sibs with tetrasomy 18p born to a mother with trisomy 18p.

Abstract

We report a family with an 18p trisomic mother and two 18p tetrasomic daughters. The mother is phenotypically normal and healthy, but with an unusual type of trisomy 18p: 47,XX,del(18)(pter-*pll.21),+i(18p) de novo. The older sister has microcephaly, mental retardation, an asymmetrical and peculiar face with low set ears, pinched up nose, high arched palate, small mouth, micrognathia, tapering fingers, asymmetrical length of legs, and an asthenic body. The younger sister was stillborn with extensive defects of the skull, congenital hydrocephalus, severe facial anomalies, and lumbosacral meningocele. Both daughters have inherited one normal chromosome 18 and an isochromosome 18p from their mother, and one normal chromosome 18 from their father. Although one quite similar family has been reported, to the best of our knowledge there have been no reports of families in which two daughters with tetrasomy 18p syndrome have been born to a mother with trisomy 18p with isochromosomes. Based on a comparative analysis of 18 cases, Rivera et all concluded that tetrasomy 18p constitutes a clinically and cyto enetically recognisable syndrome. Fryns et al gave further support to the existence of such a clinical entity. We present a family in which two daughters with tetrasomy 18p were born to a mother with de novo trisomy 18p. Case reports Case 1, a 27 month old female, was born at 37 weeks' gestation, with a birth weight of 2045 g. She showed marked psychomotor retardation. Physical examination at this age showed height 81-5 cm (-1.76 SD), weight 9-0 kg (-2.33 SD), head circum

Two-Generation Transmission of Trisomy 18p: Prenatal Diagnosis in a Woman with Mild Intellectual Disability

“…Nine cases were due to duplication of 18p (from pter to cen) [Wolff et al, 1991;Moog et al, 1994;Li et al, 1998;Grosso et al, 2005;Marical et al, 2007] or an inversion duplication of 18p [Moog et al, 1994]. Three cases of trisomy 18p with a deletion of 18p and an extra isochromosome 18p [Taylor et al, 1975;Takeda et al, 1989;Orendi et al, 2013] and 8 cases associated with a supernumerary marker chromosome [Hernandez et al, 1979;San Martin et al, 1981;Mabboux et al, 2007;Rodriguez et al, 2007;Plaja et al, 2013] have been described. Our study is the first one reporting trisomy 18p due to an unbalanced translocation dic(15; 18).…”

47,XY,+der(X)t(X;18)(p11.4;p11.22): A Unique Aneuploidy Associated with Klinefelter Syndrome due to an Extra Derivative X Chromosome Inherited Maternally

“…In order to specifically analyze the phenotype of trisomy 18p, we excluded 12 cases reported in 8 publications associated with anomalies in the structure and number of chromosomes other than 18 [Jacobsen and Mikkelsen, 1968;Gardner et al, 1978;Serville et al, 1978;Johansson et al, 1988;Moog et al, 1994;Chen et al, 2004;Lee et al, 2010;Koshy et al, 2011]. We also excluded 7 cases in 6 publications containing monosomy 18p resulting from translocation of 18p [Taylor et al, 1975;Habedank and TrostBrinkhues, 1983;Takeda et al, 1989;Oner et al, 2000;Hu et al, 2013;Orendi et al, 2013], though gain or loss of short arms of acrocentric chromosomes containing NOR regions was considered less associated with the phenotype according to some studies [Guttenbach et al, 1999;Mabboux et al, 2007]. Interestingly, complex small supernumerary marker chromosomes could also lead to the gain of 18p material.…”

Clinical Outcome: A Monosomy 18p is Better than a Tetrasomy 18p

“…Interestingly, trisomy 18p results in little phenotypic effects, and these patients have been reported to range from normal to mildly developmentally delayed [Takeda et al, 1989;Mabboux et al, 2007;Rodriguez et al, 2007;Orendi et al, 2013]. Tetrasomy 18p causes severe phenotypic effects, including moderate to severe mental retardation, hypotonia, and multiple skeletal anomalies [Ramegowda et al, 2006;Maruotti et al, 2011;Plaiasu et al, 2011].…”