Obstet Gynecol Sci.  2013 May;56(3):190-193.

A case report of prenatally diagnosed tetrasomy 18p

• Jung PS
• Won HS
• Cho IJ
• Hyun MK
• Shim JY
• Lee PR
• Kim A

Abstract

Tetrasomy 18p, one of the most commonly observed isochromosomes, consists of two copies of the p arms on chromosome 18[i(18p)]. It is known as a de novo occurrence of non-disjunction or centromeric mis-division during meiosis II in the vast majority of cases. It has a prevalence of 1/140,000-180,000 live births and affects both genders equally. A 28-year-old woman was referred at 33+2 weeks gestation to rule out fetal congenital heart disease. Her prenatal ultrasonography showed intrauterine growth retardation, cardiomegaly, and imperforate anus. Doppler ultrasonographic finding showed fetal anemia. Tetrasomy 18p was confirmed by conventional karyotyping and fluorescence in situ hybridization. Because of its very low prevalence rate, only several cases of tetrasomy 18p has been reported worldwide and it has not yet been reported in Korea before. Therefore, we report a case of prenatally diagnosed tetrasomy 18p.

Keyword

Isochromosome 18p; Prenatal diagnosis; Tetrasomy 18p

MeSH Terms

Anemia
Aneuploidy
Anus, Imperforate
Arm
Cardiomegaly
Chromosomes, Human, Pair 18
Coat Protein Complex I
Female
Fetal Growth Retardation
Fluorescence
Heart Diseases
Humans
In Situ Hybridization
Isochromosomes
Karyotyping
Korea
Live Birth
Meiosis
Pregnancy
Prenatal Diagnosis
Prevalence
Tetrasomy
Ultrasonography, Prenatal
Aneuploidy
Chromosomes, Human, Pair 18
Coat Protein Complex I

Figure

• 

  Fig. 1 (A, B) Conventional karyogram showing two copies of the p arm on chromosome 18. (C) Fluorescence in situ hybridization results using probes for the centromeric region of chromosome 18 (47,XY,+i(18)(p10)).

• 

  Fig. 2 Low-set ears with small auricles in the neonatal period.

Reference

1. Brambila Tapia AJ, Figuera L, Vazquez Cardenas NA, Ramirez Torres V, Vazquez Velazquez AI, Garcia Contreras C, et al. The variable phenotype in tetrasomy 18p syndrome: a propos of a subtle dysmorphic case. Genet Couns. 2010. 21:277–283.

2. Sebold C, Roeder E, Zimmerman M, Soileau B, Heard P, Carter E, et al. Tetrasomy 18p: report of the molecular and clinical findings of 43 individuals. Am J Med Genet A. 2010. 152A:2164–2172.

3. Dundar M, Caglayan AO, Saatci C, Cetin Z, Arslan K, Uzak AS. A case with a rare chromosomal abnormality: isochromosome 18p. Genet Couns. 2010. 21:69–74.

4. Plaiasu V, Ochiana D, Motei G, Georgescu A. A rare chromosomal disorder-isochromosome 18p syndrome. Maedica (Buchar). 2011. 6:132–136.

5. Rivera H, Moller M, Hernandez A, Enriquez-Guerra MA, Arreola R, Cantu JM. Tetrasomy 18p: a distinctive syndrome. Ann Genet. 1984. 27:187–189.

6. Ramegowda S, Gawde HM, Hyderi A, Savitha MR, Patel ZM, Krishnamurthy B, et al. De novo isochromosome 18p in a female dysmorphic child. J Appl Genet. 2006. 47:397–401.

7. Bakshi SR, Brahmbhatt MM, Trivedi PJ, Chudoba I. Constitutional tetrasomy 18p. Indian Pediatr. 2006. 43:357–360.

8. Habecker-Green JG, Naeem R, Gold H, O'Grady JP, Kanaan C, Bayer-Zwirello L, et al. Prenatal diagnosis and clinical features of an individual with tetrasomy 18p and trisomy 18q mosaicism. J Perinatol. 1998. 18:395–398.

9. Kotzot D, Bundscherer G, Bernasconi F, Brecevic L, Lurie IW, Basaran S, et al. Isochromosome 18p results from maternal meiosis II nondisjunction. Eur J Hum Genet. 1996. 4:168–174.

10. Swingle HM, Ringdahl J, Mraz R, Patil S, Keppler-Noreuil K. Behavioral management of a long-term survivor with tetrasomy 18p. Am J Med Genet A. 2006. 140:276–280.

11. Boyle J, Sangha K, Dill F, Robinson WP, Yong SL. Grandmaternal origin of an isochromosome 18p present in two maternal half-sisters. Am J Med Genet. 2001. 101:65–69.

12. Wuttikonsammakit P, Uerpairojkit B, Tanawattanacharoen S. Causes and consequences of 93 fetuses with cardiomegaly in a tertiary center in Thailand. Arch Gynecol Obstet. 2011. 283:701–706.