Which of the following is not a chromosome breakage disorder?

Ref: http://emedicine.medscape.com/article/951148- overviewExplanation:Chromosomal breakage syndromes are a group of genetic disorders that are typically transmitted in an autosomal recessive mode of inheritance.In culture, cells from affected individuals exhibit elevated rates of chromosomal breakage or instability, leading to chromosomal rearrangements.The disorders are characterized by a defect in DNA repair mechanisms or genomic instability, and patients with these disorders show increased predisposition to cancer.The following are chromosome breakage syndromes:Ataxia telangiectasia (AT)Bloom syndrome (BS)Fanconi anemia (FA)Xeroderma pigmentosum (XP)Chromosomal breakage syndromes are relatively rare: most practicing physicians may never see a patient with a chromosomal breakage syndrome,Some of the specific syndromes occur at relatively high rates in certain ethnic groups.Diagnosis is complicated because the symptoms may be varied and complex. These disorders are often lethal.