Clinical vignette: osteopathia striata with cranial sclerosis

The phenotypic spectrum of AMER1-related osteopathia striata with cranial sclerosis: The first Canadian cohort

Osteopathia striata with cranial sclerosis (OSCS; OMIM# 300373) is a rare X-linked disorder caused by mutations of the AMER1 gene. OSCS is traditionally considered a skeletal dysplasia, characterized by cranial sclerosis and longitudinal striations in the long bone metaphyses. However, OSCS affects many body systems and varies significantly in phenotypic severity between individuals. This case series focuses on the phenotypic presentation and development of individuals with OSCS. We provide an account of 12 patients with OSCS, ranging from 5 months to 38 years of age. These patients were diagnosed with OSCS after genetic testing confirmed pathogenic mutations in AMER1. Patient consent was obtained for photos and participation. Data were collected regarding perinatal history, dysmorphic features, and review of systems. This case series documents common facial dysmorphology, as well as rare extraskeletal features of OSCS, including two patients with intestinal malrotation and two patients with pyloric stenosis. We share four apparently nonmosaic males with OSCS (one de novo and three maternal variants). We also provide a clinical update on a patient who was previously published by Chénier et al. (2012). American Journal of Medical Genetics Part A, 158, 2946-2952. More research is needed to investigate the links between genotype and phenotype and assess the long-term comorbidities and overall quality of life of individuals with OSCS.

Osteopathia striata in the mandible with cranial sclerosis: a case report and review of the literature

Osteopathia striata with cranial sclerosis (OS-CS) is a bone dysplasia characterized by a linear striated pattern of sclerosis, especially in the long bones, and cranial sclerosis. It has variable clinical findings but distinctive radiological findings. Multiple oral and dental findings have been associated with this disease and can be seen during dental and/or medical imaging of the head and neck. Dentists and clinicians must be familiar with these signs to differentiate them from pathosis or erroneous radiographs. In the following case, we present a patient with OS-CS that presented at The University of Florida College of Dentistry with multiple craniofacial manifestations of this syndrome that were seen on a panoramic radiograph, which is one of the most commonly requested radiographs by dentists.

Male child with somatic mosaic Osteopathia Striata with Cranial Sclerosis caused by a novel pathogenic AMER1 frameshift mutation

Osteopathia striata with cranial sclerosis (OSCS; OMIM #300373) is a rare X-linked dominant condition caused by mutations in the AMER1 gene (also known as WTX or FAM123B). It is a condition which usually affects females in whom the clinical phenotype can be extremely variable. Conversely affected males typically die in utero or during the neonatal period [Perdu et al. (); Clinical Genetics 80: 383-388; Vasiljevic et al. (); Prenatal Diagnosis 35: 302-304]. There have been a small number of reported cases of surviving males, including three patients who are somatic mosaic for the condition [Chénier, Noor, Dupuis, Stavropoulos, & Mendoza-Londono, (); American Journal of Medical Genetics Part A 158A: 2946-2952; Holman et al. (); American Journal of Medical Genetics Part A 155A: 2397-2408; Joseph, Shoji, & Econs, (); The Journal of Clinical Endocrinology and Metabolism 95: 1506-1507]. We report a case of a male child who has proven somatic mosaicism for OSCS associated with a novel pathogenic frameshift mutation, c.607_611delAGGCC (p.Arg203 fs) in AMER1. We describe the multisystemic clinical features which include macrocephaly with ventriculomegaly and requirement for ventriculoperitoneal shunt, cleft palate, and respiratory difficulties after birth requiring tracheostomy insertion, persistent patent ductus arteriosus, failure to thrive and gastrostomy insertion, growth retardation, ophthalmoplegia, kidney malformation, cryptorchidism, and developmental delay. The use of new technologies with next generation sequencing (NGS) may improve the detection rate of mosaicism in rare conditions.

A novel sclerosing skeletal dysplasia with mixed sclerosing bone dysplasia, characteristic syndromic features, and clinical and radiographic evidence of male-male transmission

We report on a father and his 4-year-old son sharing a characteristic dysmorphic facial phenotype (including hyperteleroism, prominent forehead, and wide nasal bridge), macrocephaly, hearing loss, palatal clefting, developmental delay, hypotonia and bony abnormalities including marked cranial sclerosis and sclerosis of the ribs and long bones, which evolved in severity in the son between the ages of 2 and 4 years. The father's radiographs also showed prominent coarse striations, patchy metaphyseal sclerotic plaques, markedly increased bone density and cortical thickening of long bones, and significant degenerative changes in the thoracic spine. The son has an additional history of sleep apnea resulting from multi-level airway obstruction that includes adenoid hypertrophy, lingual tonsil hypertrophy, subglottic stenosis, and supra-arytenoid tissue consistent with laryngomalacia and tracheomalacia. The clinical, radiographic, and genetic findings in father and son are consistent with a sclerosing skeletal dysplasia syndrome with similarities to mixed sclerosing bone dysplasia (MSBD) including metaphyseal plaques, osteopathia striata, and cranial sclerosis (OS-CS). This family may represent one of the first descriptions of familial inheritance and evolving phenotype in MSBD. The evidence for male-male transmission would support the existence of an autosomal mechanism of inheritance for a novel form of MSBD with characteristic syndromic features.

WTX R353X mutation in a family with osteopathia striata and cranial sclerosis (OS-CS): case report and literature review of the disease clinical, genetic and radiological features

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.

Mosaicism in osteopathia striata with cranial sclerosis

CONTEXT

Osteopathia striata with cranial sclerosis is an X-linked dominant condition caused by mutations in the WTX gene, resulting in linear striations in long bones in combination with cranial sclerosis. This condition is usually lethal in males. OBJECTIVE/PATIENT: Our aim was to determine the underlying genetic cause in a 37-yr-old male with this condition.

DESIGN

DNA sequencing of peripheral blood and hair was performed to identify mutations in WTX. Quantitative PCR was performed to determine gene copy number variation.

RESULTS

DNA sequenced from peripheral blood revealed the presence of two alleles at the 1108th position of the WTX gene. Subsequent DNA sequencing of hair follicles and quantitative PCR confirmed the presence of mosaicism.

CONCLUSION

A novel mutation (c.1108G>T) found in our patient results in a truncated protein (E370X). Our patient represents the first confirmed case of mosaicism in osteopathia striata with cranial sclerosis.

Surgically assisted rapid maxillary expansion in two cases of osteopathia striata with cranial sclerosis

Osteopathia striata with cranial sclerosis (OS-CS) is a rare skeletal dysplasia characterized by linear striations of the long bones, osteosclerosis of the cranium, and extraskeletal anomalies. Osteosclerosis of the cranial and facial bones can lead to disfigurement and to disability due to the pressure on the cranial nerves. We report two cases of OS-CS where surgically assisted rapid maxillary expansion was performed for widening the extremely narrow maxilla. One should be aware of the disease-related problems and the possible complications that might occur with this type of patient.

Osteopathia striata with cranial sclerosis: clinical, radiological, and bone histological findings in an adolescent girl

Osteopathia striata with cranial sclerosis (OS-CS) is a rare skeletal dysplasia characterized by linear striations of the long bones, osteosclerosis of the cranium, and extra-skeletal anomalies. We provide a comprehensive description of the skeletal phenotype in a French-Canadian girl with a moderate to severe form of sporadic OS-CS. Multiple medical problems, including anal stenosis and the Pierre-Robin sequence, were evident in the first few years of life. At 14 years, she was fully mobile, with normal intellect and stature. She suffered chronic lower extremity pain in the absence of fractures, as well as severe headaches, unilateral facial paralysis, and bilateral mixed hearing loss. Biochemical indices of bone and mineral metabolism were within normal limits. Bone densitometry showed increased areal bone mineral density in the skull, trunk, and pelvis, but not in the upper and lower extremities. An iliac bone biopsy specimen revealed an increased amount of trabecular bone. Trabeculae were abnormally thick, but there was no evidence of disturbed bone remodeling. In a cranial bone specimen, multiple layers of periosteal bone were found that covered a compact cortical compartment containing tightly packed haversian canals. Bone lamellation was normal in both the iliac and skull samples. Osteoclast differentiation studies showed that peripheral blood osteoclast precursors from this patient formed functional osteoclasts in vitro. Thus, studies of bone metabolism did not explain why bone mass is increased in most skeletal areas of this patient. Cranial histology points to exuberant periosteal bone formation as a potential cause of the cranial sclerosis.

Osteopathia striata cranial sclerosis: non-random X-inactivation suggestive of X-linked dominant inheritance

Osteopathia striata with cranial sclerosis (OS-CS) is a rare syndrome comprising macrocephaly, minor anomalies, conductive hearing loss, and mild mental retardation. The diagnosis is based on radiological findings, including cranial sclerosis and longitudinal striations of metaphyses of long bones. Here we report on 10 new cases of OS-CS, including two sporadic cases and three families, with an excess of affected females (9F/1M). Phenotypic variability was observed in our patients as well as several unusual findings. Hirschsprung disease, Pierre Robin sequence, coronal craniostenosis, and laryngotracheomalacia were associated with a poor prognosis. The X-inactivation pattern of peripheral blood lymphocytes in a mildly affected mother and her severely affected boy demonstrated a non-random X-inactivation in the mother. This finding, in combination with a sex ratio in favor of females and an increased morbidity and mortality in males, is highly suggestive of X-linked dominant inheritance.