Structural anomaly of chromosome 18 with Edward syndrome phenotype

B. Krishnamurthy, M. R. Savitha, Pratibha Patil

Abstract


Edward syndrome has a median survival time of 14.5 days. Importance of this case report is in the rarity of this karyotype and prolonged survival as compared with complete trisomy 18. A 5-year-old male child with global developmental delay had brachycephaly, microstomia, narrow palatal arch, low set ears, widely spaced nipples, diastasis recti, bilateral cryptorchidism, ulnar deviation of both hands with absent distal creases, rocker bottom foot with overlapping of second and third toes. Cardiac, ophthalmological, otolaryngological evaluations, ultrasonography abdomen, and skeletal survey were normal. Computed tomography head showed mild dilatation of lateral ventricles. Karyotyping revealed 46 chromosomes with an asymmetry of chromosome 18. Pathognomonic segment responsible for Edwards phenotype is in the q arm of chromosome 18. In this patient, there was no complete trisomy 18. However, there was an abnormality in the form of asymmetry that can be due to either isochromosome 18q, translocation chromosome 18 or duplication of the critical region.


Keywords


Edward syndrome, Structural anomaly, Chromosome 18

Full Text:

PDF

References


Kumar V, Abbas AK, Fausto N. Genetic disorders. In: Kumar V, Abbas AK, Fausto N, editors. Robbins and Cotran Pathologic Basis of Disease. 7th Edition. Philadelphia: Saunders Elsevier; 2008: 145-93.

Jones KL. Recognisable patterns of malformation. In: Jones KL, editor. Smith’s Recognizable Patters of Human Malformation. 6th Edition. Philadelphia: Saunders Elsevier; 2009: 13-5.

Pal S, Siti MI, Ankathil R, Zilfalil BA. Two cases of isochromosome 18q syndrome. Singapore Med J. 2007;48(5):e146-50.

Sutton HE. Chromosomal abnormalities: structural. In: Sutton HE, editor. An Introduction to Human Genetics. 4th Edition. Florida: Harcourt Brace Jovanovica; 1988: 175-96.

Jordey LB, Carey JC, Bamshad MJ, White RL, Cytogenetics: chromosomal basis of human disease. In: Jordey LB, Carey JC, Bamshad MJ, White RL, editors. Medical Genetics. 3rd Edition. Missouri: Mosby Elsevier; 2008: 107-35.

Müller H, Bühler EM, Signer E, Egli F, Stalder GR. Trisomy-18 syndrome caused by translocation or isochromosome formation. A case report with bibliography. J Med Genet. 1972;9(4):462-7.

Boghosian-Sell L, Mewar R, Harrison W, Shapiro RM, Zackai EH, Carey J, et al. Molecular mapping of the Edwards syndrome phenotype to two noncontiguous regions on chromosome 18. Am J Hum Genet. 1994;55(3):476-83.