RECQL4 and Bloom syndrome: In contrast, individuals with BS can be differentiated by the presence of microcephaly, immunodeficiency, and type 2 diabetes, whereas patients with a RECQL4-associated disorder can be identified by absent or hypoplastic thumbs, radial ray defects, absent or hypoplastic patellae, limb malformations, cataracts, reduced bone density, anemia, neutropenia, and craniosynostosis.