ANALYSIS OF A TERMINAL XP22.3 DELETION IN A PATIENT WITH 6 MONOGENIC DISORDERS - IMPLICATIONS FOR THE MAPPING OF X-LINKED OCULAR ALBINISM

The molecular characterisation of chromosomal aberrations in Xp22.3 ha s established the map position of several genes with mutations resulti ng in diverse phenotypes such as short stature (SS), chondrodysplasia punctata (CDPX), mental retardation (MRX), ichthyosis (XLI), and Kallm ann syndrome (KAL). We describe the clinical symptoms of a patient wit h a complex syndrome compatible with all these conditions plus ocular albinism (OA1). He has a terminal Xp deletion of at least 10 Mb of DNA . Both the mother and sister of the patient are carriers of the deleti on and show a number of traits seen in Turner's syndrome. The diagnosi s of ocular albinism was confirmed in the patient and his mother, who shows iris translucency, patches and streaks of hypopigmentation in th e fundus, and macromelanosomes in epidermal melanocytes. By comparativ e deletion mapping we can define a deletion interval, which locates th e OA1 gene proximal to DXS143 and distal to DXS85, with the breakpoint s providing valuable starting points for cloning strategies.