A 2-week-old baby is suffering from cri du chat syndrome , which of the following karyotype is the probable karyotype of the baby (AIIMS May 2013)
Children with chromosome abnormalities often exhibit poor growth (failure to thrive) and developmental delay with an abnormal facial appearance. This baby is too young for developmental assessment, but the catlike cry should provoke suspicion of cri-du-chat syndrome.
i. Cri-du-chat syndrome is caused by deletion of the terminal short arm of chromosome 5 [46,XX,del(5p), also abbreviated as 5p-] as depicted in panel.
ii. When a partial deletion or duplication like this one is found, the parents must be karyotyped to determine if one carries a balanced reciprocal translocation.
a. The other karyotypes show
i. deletion of the short arm of chromosome 4 [46,XY,del(4p) or 4p-];
ii. XYY syndrome (47,XYY);
iii. Klinefelter’s syndrome (47,XXY).