Tetrasomy 18p: case report and review of literature

Abstract

Shahad Bawazeer,1 Maha Alshalan,2 Aziza Alkhaldi,3 Nasser AlAtwi,3 Mohammed AlBalwi,1,3,4 Abdulrahman Alswaid,2 Majid Alfadhel,1,2,4 1Developmental Medicine Department, King Abdullah International Medical Research Center, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia; 2Department of Pediatrics, Genetic Division, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia; 3Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia; 4King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia Abstract: Tetrasomy 18p syndrome (Online Mendelian Inheritance in Man 614290) is a very rare chromosomal disorder that is caused by the presence of isochromosome 18p, which is a supernumerary marker composed of two copies of the p arm of chromosome 18. Most tetrasomy 18p cases are de novo cases; however, familial cases have also been reported. It is characterized mainly by developmental delays, cognitive impairment, hypotonia, typical dysmorphic features, and other anomalies. Herein, we report de novo tetrasomy 18p in a 9-month-old boy with dysmorphic features, microcephaly, growth delay, hypotonia, and cerebellar and renal malformations. We compared our case with previously reported ones in the literature. Clinicians should consider tetrasomy 18p in any individual with dysmorphic features and cardiac, skeletal, and renal abnormalities. To the best of our knowledge, we report for the first time an association of this syndrome with partial agenesis of cerebellar vermis. Keywords: tetrasomy 18p, chromosomal, isochromosome, 18p, dysmorphic, CGH microarray, chromosome, syndrome

Keywords

• Tetrasomy 18p
• Chromosomal
• Isochromosome
• 18p
• Dysmorphic
• CGH microarray