PNCK and cerebral creatine deficiency syndrome: The third female (RM-1619) carried a de novo deletion at Xq28 (chrX:152925630-153027220), spanning the genes ABCD1, associated with X-linked adrenoleukodystrophy (MIM #300100), BCAP31, associated with X-linked deafness, dystonia, and cerebral hypomyelination (MIM #300475), SLC6A8, associated with cerebral creatine deficiency syndrome (MIM #300352), and PNCK (MIM *300680).