Introduction
X-linked ID type Nascimento (XLID), characterized by a syndromic intellectual disability due to gene mutation on the X chromosome, has great attention caused by the high incidence rate of males in intellectual disability [1-5]. According to recent reports, almost 15 percent of the X-chromosome genes that is known to be related to intellectual disability, while only accounts for about 5 percent of the human genome[6]. However, the majority of mutations in XLID genes remain unknown.
Ubiquitin-conjugating enzyme E2 (UBE2A), involved in the proteasome pathway of protein degradation and DNA repair [7], is located on Xq24 [8-10]. UBE2A deficiency syndrome, also known as X-linked ID type Nascimento (MIM #300860), was first described by Nascimento in 2006, which was characterized clinically by pronounced retardation of psychomotor development, wide face, synophrys, generalized hirsutism, urogenital abnormalities [11]. Since then, two splice-site mutations in UBE2A, seven missense mutations in UBE2A, and four larger deletions in UBE2A have been found [7, 12]. However, there have been fewer reports of UBE2A splice site mutation in china.
Here, we report a Chinese patient diagnosed with XLID, and a novel UBE2A splice site mutation (c.241+1 G>A). In addition to the clinical features of white matter abnormalities in MRI and a recognizable face like wide faces are the same as the typical features reported in XLID. Moreover, the novel clinical features of erected head unstable, no hirsutism, no synophrys,healthy heart, were found. Taken together, the finding of novel mutations of UBE2A in XLID will be better to prevent disability in humans and more possibility to explore the molecular basis of intellectual disability.