Abstract
Osteopathia striata with cranial sclerosis (OS-CS) or Horan-Beighton syndrome is a rare X-linked dominant inherited bone dysplasia, characterized by longitudinal striations of long bones and cranial sclerosis. Patients can be asymptomatic or present with typical facial dysmorphism, sensory defects, internal organs anomalies, growth and mental retardation, depending on the severity of the disease. WTX gene (Xq11) has been recently identified as the disease causing gene. Aim of this article is to present the case of a 6 year old girl initially evaluated for bilateral hearing loss. Patient’s head CT scan pointed out sclerosis of skull base and mastoid cells, and abnormal middle-ear ossification. Clinical examination of the patient and her mother were suspicious for OS-CS. The diagnosis was confirmed by X-rays examination showing typical longitudinal striation. Genetic analysis allowed the identification of maternally transmitted heterozygous nonsense c.1057C>T (p.R353X) WTX gene mutation. We also provide a systematic review of currently available knowledge about clinical, radiologic and genetic features typical of the OS-CS.
Highlights
Osteopathia striata with cranial sclerosis (OS-CS; OMIM#300373) is a rare, X-linked dominant inherited skeletal dysplasia, part of sclerosing bone dysplasias [2-4], a group of disorders characterized by abnormally dense bones as a result of the prevalence of bone formation by osteoblasts over bone reabsorption by osteoclasts
Striated methaphyses were firstly described by Voorhoeve in 1924 [5]; thirty years later, Hurt [3] reported a case of association with cranial sclerosis
Aim of this paper is to present the first case of OS-CS with maternal transmission of a heterozygous 1057C>T WTX gene mutation, and to summarize currently available knowledge on OS-CS clinical, radiological and genetic features
Summary
Osteopathia striata with cranial sclerosis (OS-CS; OMIM#300373) is a rare, X-linked dominant inherited skeletal dysplasia (prevalence 0.1/1 million people [1]), part of sclerosing bone dysplasias [2-4], a group of disorders characterized by abnormally dense bones as a result of the prevalence of bone formation by osteoblasts over bone reabsorption by osteoclasts. Sequencing of the entire coding region of WTX was performed as previously described [7] and allowed the identification of the heterozygous nonsense mutation c.1057C>T, leading to a truncated protein (p.R353X) (Figure 3b). This mutation had been previously reported as a de novo mutation only in two sporadic cases [8]. Craniofacial dysmorphism Skull thickening (cranial sclerosis) is the most typical and early feature [1,6,8,10-37] (85%), often presenting before longitudinal bone striations, and typically affects cranial vault, base and some facial bones, leading to sinuses obliteration and reduction of mastoid pneumatization [1,10,12-14,19,21,26,33,34] (sometimes responsible for Figure 3 X-ray of the patient’s femur showing OS-CS typical bone longitudinal striations (a). Mutations associated to WTX-interacting proteins have been advocated to explain tumor development [8]
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