Perinatal findings and molecular cytogenetic analysis ofde novo partial trisomy 16q (16q22.1?qter) and partial monosomy 20q (20q13.3?qter)

Abstract

Partial trisomy 16q (16q22.1-->qter) and partial monosomy 20q (20q13.3-->qter) may be associated with the perinatal findings of IUGR, dolichocephaly, hypotonia, cleft palate, congenital heart defects, a subependymal cyst, and hypospadia. SKY, FISH, and genetic marker studies help in delineating the parental origin and the regions of the deletion and duplication in the de novo unbalanced translocation.

Major feeding difficulties in the first reported case of interstitial 20q11.22‐q12 microdeletion and molecular cytogenetic characterization

“…Considering the nine reported cases with interstitial chromosome 20q deletion [Fraisse et al, 1981;Petersen et al, 1987;Porfirio et al, 1987;Shabtai et al, 1993;Aldred et al, 2002;Chen et al, 2005;Genevieve et al, 2005], only one patient has a common deleted region with our patient (del(20) (q11.23-q13.11)) although different breakpoints [Petersen et al, 1987]. The clinical features of this 4-year-old boy are not well described, and include facial dysmorphism with strabismus, broad nasal bridge, low-set ears, macrostomia, psychomotor retardation, febrile seizures, and heart murmur.…”

“…To date, only nine cases have been reported in the literature [Fraisse et al, 1981;Petersen et al, 1987;Porfirio et al, 1987;Shabtai et al, 1993;Aldred et al, 2002;Chen et al, 2005;Genevieve et al, 2005]. Except the case reported by Petersen et al [1987] with more proximal breakpoints, the other deletions are located at the distal extremity of chromosome 20q.…”

Severe upper airway stenosis in a boy with partial monosomy 16p13.3pter and partial trisomy 16q22qter

“…The accurate segment of deletion in 16p or duplication in 16q has not been ascertained and involvement of other chromosomal rearrangements could not be excluded because array-based comparative genomic hybridization (CGH) was not performed. Partial monosomy 16p13.3 and partial trisomy 16q22 have various clinical similarities, including a prominent forehead, downslanting palpebral fissures, a thin upper lip, a high arched palate, ear abnormalities, clinodactyly, congenital heart defects and renal anomalies (Hennekam et al 1993;Eussen et al 2000;Petrij et al 2000;Brisset et al 2002;Chen et al 2005). Additionally, partial monosomy 16p13.3 features a heavy or highly arched eyebrows, long eyelashes, a nasal septum below alae, a beaked nose, broad thumbs, radially deviated thumbs, broad terminal phalanx of fingers, varus/valgus angulation of halluces, duplicated halluces, cryptorchidism, and alfa-thalassemia (Hennekam et al 1993;Eussen et al 2000;Petrij et al 2000).…”

“…Partial trisomy 16q is a rare chromosomal abnormality, usually associated with a balanced translocation or pericentric inversion in a parent (Chen et al 2005). Partial monosomy 16p has been reported more frequently, and could cause alfa-thalassemia/mental retardation syndrome, deletion-type (ATR-16), Rubinstein-Taybi syndrome (RTS), and a contiguous gene syndrome with tuberous sclerosis 2 (TSC2) and polycystic kidney disease 1 (PKD1) (Wilkie et al 1990;Petrij et al 1995;Sampson et al 1997).…”

First Report of Low-Rate Mosaicism for 20q11.21q12 Deletion and Delineation of the Associated Disorder

“…To date, 24 unrelated patients have been reported [Fraisse et al, 1981;Petersen et al, 1987;Porfirio et al, 1987;Shabtai et al, 1993;Aldred et al, 2002;Chen et al, 2005;Genevieve et al, 2005;Callier et al, 2006;Borozdin et al, 2007;Iqbal and Al-Owain, 2007;Hiraki et al, 2011;Gervasini et al, 2013;Iourov et al, 2013;Santoro et al, 2013;Posmyk et al, 2014;Jedraszak et al, 2015;Meredith et al, 2017], including 12 with deletions involving the proximal 20q11.2 region [Callier et al, 2006;Iqbal and Al-Owain, 2007;Hiraki et al, 2011;Gervasini et al, 2013;Iourov et al, 2013;Posmyk et al, 2014;Jedraszak et al, 2015;Meredith et al, 2017]. The clinical phenotype shared by these latter patients includes prenatal and postnatal growth retardation, feeding difficulties, psychomotor retardation and intellectual disability of variable degree, craniofacial dysmorphisms (high forehead, frontal bossing, deep-set eyes, midface hypoplasia), and hand/ feet anomalies such as brachydactyly and clinodactyly.…”