Tetraploidy in a 15‐month‐old girl

Abstract

We present a 15-month-old girl with tetraploidy and compare the manifestations with those of 3 previously reported liveborn infants with the same type of polyploidy. Common anomalies noted included micro-turricephaly, a prominent but narrow forehead, microphalmia or anophthalmia, limb anomaly, sacral meningomyelocele, and mental retardation.

Polyploid Incidence and Evolution

“…Consistent with what is known about imprinting in mammals, digynic triploids develop at an appropriate rate but display stunted growth, while dispermic triploids are larger than expected based on their developmental stage (80). Tetraploid newborns, both XXXX [female (107)] and XXYY (male (72)], have been reported and are thought to result from a failure of cell division in the zygote. Although polyploidy can disrupt normal sexual development and cause abnormal genital formation in humans (102), the fact that polyploid survival is much lower than that of trisomics involving the sex chromosomes (XYY, XXY, and XXX) and is associated with much more severe abnormalities and early mortality regardless of genotype suggest that a general disruption of development and not a disruption of sexual development, per se, explains the absence of polyploidy in adult humans.…”

“…Approximately 5% of natural abortuses are polyploid (28). Although most triploids and tetraploids have severe defects and fail to survive to term, livebirths do occasionally occur with infants surviving for up to two years (55,107). Imprinting has been implicated as a possible mechanism causing developmental abnormalities in triploids (32,80), based on the observation that survival is higher for digynic triploids (formed from polyploidization in the egg) than for dispermic triploids (formed from polyploidization in the sperm or, more commonly, fertilization by two sperm).…”

Mixoploidy in humans: Two surviving cases of diploid‐tetraploid mixoploidy and comparison with diploid‐triploid mixoploidy

“…We describe the phenotype in older patients, and it bears Wilson et al, 1988, with additional data from Donnai et al, 1988;Aughton et al, 1988;Shiono et al, 1988;Lopes-Pajares et al, 1990;Lafer and Neu., 1988;Morris and Lustgarten, 1988;Wullich et al, 1991;Urioste et al, 1990. Prominent forehead 7/15 5/9 Frequent 3/5 some similarity to that seen in older patients with 2d3n mixoploidy. A 21-year-old patient [Fryns et al, 19801 and a 14-year-old patient [Edwards et al, 19891 (Fig.…”

“…There have been 8 neonates reported with complete tetraploidy [Golbus et al, 1976;Pitt et al, 1981;Scarbrough et al, 1984;Lafer and Neu, 1988;Shiono et al, 1988;Lopez-Pajaves et al, 19901. They have demonstrated intrauterine growth deficiency, hypotonia, microcephaly with prominent forehead, small pinched nose, cleft lip and/or palate, small palpebral fissures, microphthalmia and/or coloboma, apparently low-set "dysplastic" ears with occasional preauricular tags, long slender limbs and digits with positional deformation, and occasional CNS, heart, and genitourinary defects.…”

Diploid/tetraploid/t(1;6) mosaicism in a 17‐year‐old female with hypomelanosis of Ito, multiple congenital anomalies, and body asymmetry

“…In terms of short-term survival, there are a number of descriptions of newborns or young children with either complete tetraploidy [Golbus et al, 1976;Pitt et al, 1981;Scarbrough et al, 1984;Lafer and Neu, 1988;Shiono et al, 1988;Lopez Pajares et al, 1990] or mosaic tetraploidy [Kohn et al, 1967;Kelly and Rary, 1974;Reddy et al, 1977;Veenema et al, 1982;Quiroz et al, 1985;Aughton et al, 1988;Wilson et al, 1988;Urioste et al, 1990;Wullich et al, 1991;Roberts et al, 1996]. Most died as infants or young children.…”