A 6 Year Old with Characteristics Similar to Russell Silver and Downs Syndrome Identified as Klinefelter Proband

First described by Klinefelter et al. 1942, this syndrome (KS) is a chromosomal disorder represented by most of the patients with a genotype of 47XXY, and approximately 15% of them are mosaics with variable phenotype. The cytogenetic and biochemical investigations of a 6 year old mosaicism Klinefelter syndrome boy lacking typical clinical features such as tall stature or gynaecomastia but presenting other clinical features such as short stature, asymmetrical body, sparse eyebrows, low set ears, broad nasal ridge, small penis and small testis dysmorphic with Down’s and Russell silver syndrome have been reported. Karyotype from whole blood culture revealed mosaicism with a few number of cells showing the syndrome genotype 47 XXY (24%) and the predominant cell line being normal 46 XY (62%). This was confirmed by fluorescence in situ hybridization (FISH). This is the youngest case to be reported for Klinefelter syndrome as diagnosis is often missed or delayed till adulthood because of the low index of suspicion.