Copy Number Gain at Xq28 in a Child with Global Developmental Delay Associated with a Variant Form of Hoyeraal-Hreidarsson Syndrome.

We report the case of a child from Central Brazil with global developmental delay (GDD), syndromic features, and absence of abnormal skin pigmentation, nail dystrophy, and leukoplakia of the oral mucosa, with a rearrangement at Xq28 harboring the DKC1 gene. GTC-banding revealed a male karyotype (46,XY) with no visible numerical or structural alterations. Chromosomal microarray analysis (CMA) showed a 0.36-Mb gain at Xq28 of maternal origin, encompassing 22 genes, including DKC1 . Rearrangements and mutations involving this gene have been associated with dyskeratosis congenita, X-linked (OMIM 305000) and Hoyeraal-Hreidarsson syndrome. CMA was a powerful and efficient approach to identify a gain at Xq28 harboring the DKC1 gene in our patient with GDD syndromic features and no cutaneous alterations, suggesting that this variant is associated with the Hoyeraal-Hreidarsson syndrome.
Competing Interests: The authors have no conflicts of interest to declare.
(Copyright © 2019 by S. Karger AG, Basel.)