Complex glycerol kinase deficiency leads to psychomotor and body-growth failure

Chronic granulomatous disease associated with Duchenne muscular dystrophy caused by Xp21.1 contiguous gene deletion syndrome: Case report and literature review

Chronic granulomatous disease (CGD) and Duchenne muscular dystrophy (DMD) are X-linked recessive disorders whose genes are 4.47 Mb apart within Xp21.1. A combination of both diseases is rare with only five cases reported in the literature where it is known as Xp21.1 "contiguous gene deletion syndrome". We describe a male neonate who presented with sepsis at 19 days of age. The diagnosis of CGD with DMD was established through copy number variation sequencing (CNV-seq) with an extensive 7.5 Mb deletion of Xp21.2-Xp11.4 of the proband. One of his elder sisters and his mother are carriers. The deletion includes six known genes: glycerol kinase (GK), dystrophin (DMD), cilia- and flagella-associated protein 47 (CFAP47), gp91 (CYBB), Kell antigen (XK), and retinitis pigmentosa GTPase regulator (RPGR). Laboratory assays revealed an increased creatine kinase (CK) level, decreased gp91 expression, and a positive nitroblue tetrazolium test. Due to the extensive gene deletion and the poor prognosis, the family determined to pursue conservative management without further laboratory workup. The patient passed away from a fulminant infection at the age of three-month at a local medical facility. To the best of our knowledge, this case of Xp21.1 contiguous gene deletion syndrome represents the most extensive deletion of genes in this region ever reported. A literature review of similar cases is presented.

The diagnostic difficulties of complex glycerol kinase deficiency

We describe 2 siblings with the contiguous X-linked gene deletion syndrome, complex glycerol kinase deficiency. The elder sibling demonstrated the difficulties diagnosing this rare condition. Affected children have the combined complications of congenital adrenal hypoplasia, Duchenne muscular dystrophy, and glycerol kinase deficiency. These patients illustrate the importance of genetic testing and prepregnancy counseling. In addition, they demonstrate the need for a multidisciplinary team approach in their management.