frank has klinefelter syndrome (47, XXY)... Frank has Klinefelter syndrome (47, XXY). His mother has normal skin, but his father has anhidrotic ectodermal dysplasia, an X-inked condition where the skin does not contain sweat glands. Frank has patches of normal skin and patches of skin without sweat glands. Complete the sentences. Some answers may be used more than once or not at all. Frank received the mutant chromosome from his. Nondisjunction occurred in his during the meiotic division. Solution Answer Frank recieved the mutant chromosome from his Father Nondisjunction occured in his Father during the First meiotic division. Since, the mutant gene is present on X-chromosome of Father of Frank Frank has also got this disease, therefore, the second chromosome of XXY combination must have been inherited from father. Nondisjunction has occured at Meiosis- 1 Stage, At meiosis -1 chromosomes separate (Not chromatids), therefore, one cell has recieved both chromosomes (XY) Each chromosomes is made up of 2 chromatids. At Meiosis -II chromatids separate. therefore, the sperm from such a cell recieves one chromatids from X and another chromatids from Y and forms XY combination when this sperm with XY fuses with egg having X, there resultant zygote has XXY genotype.