Case Study: Patient with 7p14–P21 Deletion Spanning the TWIST Gene and the HOXA Gene Cluster

Abstract

Introduction: While several literature reports have been published about patients with microdeletions within chromosome 7p, only a small fraction of those reports is specific to deletions that encompass the TWIST gene and HOXA gene cluster.  The large-span deletions within this cluster result in haploinsufficiency of six genes known to have a role in different autosomal dominant genetic disorders: TWIST1, GSDME (DFNA5), CYCS, HOXA11, HOXA13, and GARS.  Deletion of TWIST1 gene on 7p21 and deletion of HOXA cluster on 7pl5.2 lead to Saethre-Chotzen syndrome and to hand-foot-genital syndrome, respectively. Objectives: Our patient presented with a phenotype combining Saethre-Chotzen syndrome (SCS) and hand-foot-genital syndrome (HFS), which is similar to previously reported cases with a deletion spanning 7p21– p14.3. The objective of our report is to correlate the clinical observations with the patient’s genetic test result, namely 46,XY,del(7)(p14p21). Patient and Methods: We describe a patient who had manifestations of SCS and HFU, caused by an interstitial deletion of chromosome 7p21–p14 detected by RHG band. Results and Conclusion: We therefore confirm previous reports that microdeletions of 7p spanning the TWIST gene and HOXA gene cluster lead to a clinically recognizable ‘haploinsufficiency syndrome’.  All of the features of this patient could be accounted for by combined effect of the deletion of the TWIST and HOXA cluster.