UBE2A deficiency syndrome: a report of two unrelated cases with large Xq24 deletions encompassing UBE2A gene

Intragenic mutations of the UBE2A gene, as well as larger deletions of Xq24 encompassing UBE2A have in recent years been associated with a syndromic form of X-linked intellectual disability called UBE2A deficiency syndrome or X-linked intellectual disability type Nascimento (OMIM#300860). Common clinical features in these patients include moderate to severe intellectual disability (ID), heart defects, dysmorphic features such as high forehead, synophrys, prominent supraorbital ridges, almond-shaped and deep-set eyes, wide mouth, myxedematous appearance, hirsutism, onychodystrophy, and genital anomalies. This study investigates clinical and molecular data of two unrelated, affected males with chromosome Xq24 deletions encompassing UBE2A. Both have been followed from birth until two years of age. A review of the previously published patients with deletions encompassing UBE2A is provided. Besides the common features, the two boys show anomalies not previously described, such as retinal coloboma, esophageal atresia with esophageal fistula, long fingers, camptodactyly, clinodactyly, and long broad toes. Analyses of the phenotype-genotype correlations suggest considerable prevalence of heart defects in the group of patients with larger deletions of Xq24 in comparison to the patients having intragenic UBE2A mutations. However, further studies are needed in order to establish statistically reliable phenotype-genotype correlations of this syndrome.