A Dysmorphic Child with a Pericentric Inversion of Chromosome 8

An 8-year-old boy was referred to our institute with dysmorphic features such as mild lupus, micrognathia, low hair line, hypoplasia, hemi atrophy of left side of the face, abnormal size of ears, hypothenar, hypoplasia of chin, and tongue tie. MRI scan was found to be normal and EEG suggestive of generalized seizure disorder. Cytogenetic evaluation of the proband revealed a pericentric inversion of chromosome 8 with 46, XY, and inv 8 (p11.2; q21.2) karyotype. 1. Introduction Pericentric inversions are among the frequent chromosomal rearrangements associated with genetic disorders with a frequency of 1-2% [1, 2]. Pericentric inversions result from a two-break event which occurs between the short (p) and the long arms (q) within the chromosome followed by a 180° rotation of the intercalary segment. The phenotype of the inversion carrier depends on the type of inversion, size of the inverted part, and the chromosome involved [3]. In this report, we describe the distinct clinical phenotype and the karyotype of a boy with dysmorphic facial features and mild mental retardation associated with a pericentric inversion of chromosome 8. 2. Case Report An 8-year-old male child with dysmorphic facies and mild mental retardation was referred to the Institute of Genetics, Hyderabad for cytogenetic evaluation. He was born after full term as the third child in the sibship of nonconsanguineous parents. He had delayed developmental milestones, neck holding at the age of 5 months, walking independently at the age of 2 years and 5 months, and started speech at the age of 3 years and 5 months. The dysmorphic facial features included mild lupeus, micrognathia, low-hair line, hypoplasia, hemiatrophy of left side of the face, abnormal size of ears, hypothenar, hypoplasia of chin, and tongue tie. His external genitalia were normal. Psychological evaluation of the child was carried out using Senguin form board and Vineland Social maturity physical examination scale [4]. The intelligent quotient was found to be 64 indicative of mild mental retardation. MRI Scan report of the propositus was normal, but his EEG study was suggestive of generalized seizure disorder. He had hyperactive behavior with slurred speech. It is informed that the boy was frightened by loud sounds and is presently attending a special school. Chromosomal analysis of peripheral blood lymphocytes was performed using GTG banding for the propositus and their parents [5, 6]. A rearranged chromosome was observed in the propositus with pericentric inversion of chromosome 8 with break point at p 11.2 and q 21.2 regions