Split‐hand/foot malformation (SHFM) with long‐bone deficiency (SHFLD) is a rare condition characterized by SHFM associated with long‐bone malformation usually involving the tibia. It includes three different types; SHFLD1 (MIM % 119,100), SHFLD2 (MIM % 610,685) and SHFLD3 (MIM # 612576). The latter was shown to be the most commonly reported with a duplication in the 17p13.1p13.3 locus that was narrowed down to the BHLHA9 gene. Here, we report a consanguineous Lebanese family with three members presenting with limb abnormalities including tibial hemimelia. One of these patients presented with additional bowing fibula and another with bilateral split hand. CGH array analysis followed by RQ‐PCR allowed us to detect the first homozygous duplication on the short arm of chromosome 17p13.3 including the BHLHA9 gene and involved in SHFLD3. Interestingly, one patient with the homozygous duplicated region, carrying thus four BHLHA9 copies presented with long bone deficiency but no SHFM. The incomplete penetrance and the variable expressivity of the disease in this family as well as the presence of the BHLHA9 homozygous duplication rendered genetic counseling extremely challenging and preimplantation genetic diagnosis almost impossible.
Spondyloocular syndrome (SOS, OMIM # 605822) is a rare genetic disorder characterized by osseous and ocular manifestations, including generalized osteoporosis, multiple long bones fractures, platyspondyly, dense cataracts and retinal detachment, and dysmorphic facial features, with or without short stature, cardiopathy, hearing impairment, and intellectual disability. Biallelic mutations in the XYLT2 gene (OMIM * 608125), encoding the xylosyltransferase II, were shown to be responsible for this disease. To date, 22 cases with SOS have been described, with varying clinical presentations and a yet-to-be-established genotypic–phenotypic correlation. Two patients from a consanguineous Lebanese family that presented with SOS were included in this study. Whole exome sequencing revealed a novel homozygous nonsense mutation in XYLT2 (p.Tyr414*) in these patients. We review all previously reported cases with SOS, describe the second nonsense mutation in XYLT2, and contribute to a better delineation of the phenotypic spectrum of the disease.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.