Osteopathia Striata-Cranial Sclerosis Syndrome

Osteopathia striata with cranial sclerosis (OS-CS) is a bone dysplasia characterized by longitudinal striations of the metaphyses of the long bones, sclerosis of the craniofacial bones, macrocephaly, cleft palate and hearing loss.

Epidemiology

Fewer than 100 cases have been reported in the literature.

Clinical description

The clinical presentation is highly variable even within the same family, ranging from mild skeletal manifestations to multisystem organ involvement. Cardiac malformations (ventricular septal defect, aortic stenosis), developmental delay, cranial nerve palsies, anal malformations, cataracts and nervous system malformations are frequent. Vertebral anomalies (scoliosis, spondylolisthesis), anomalies of extremities (clubfoot, unusually long and thin fingers with clinodactyly of distal phalanges), hypertelorism, frontal bossing, broad nasal bridge, prominent occipital bony protrusion and mild intellectual impairment have also been documented. In rare cases, OS-CS has been reported in association with Hirschsprung disease, Pierre Robin sequence, coronal craniostenosis, hydrocephalus and laryngotracheomalacia (see these terms).

Etiology

OS-CS is associated with mutations in the Wilms tumour gene on the X chromosome (WTX), a repressor of WNT signaling (beta-catenin pathway implicated in control of target genes in the nucleus).

Diagnostic methods

Diagnosis is based on clinical and radiological examination, which reveals cranial sclerosis, longitudinal striations in the widened metaphyses of the long bones, and sclerosis of the ribs. Genetic testing is available to confirm the diagnosis.

Differential diagnosis

Differential diagnosis includes a large number of conditions with primary or secondary bone sclerosis. As the macrocephaly seems to be an early and constant clinical feature, OS-CS should be considered in the differential diagnosis of fetuses/infants with unexplained macrocephaly.

Antenatal diagnosis

In the most severe cases, the disorder can be diagnosed prenatally by detection of increased biparietal diameter of the fetal head on ultrasound examination. Prenatal genetic diagnosis is available if the disease-causing mutation in the family is known.

Genetic counseling

OS-CS follows an X-linked dominant pattern of inheritance, with frequent lethality in males.

Management and treatment

Management is supportive and aims at providing multidisciplinary surveillance and symptomatic management of complications.

Prognosis

Cases with severe multiple manifestations and those associated with Hirschsprung disease, Pierre Robin sequence and coronal craniostenosis have poor prognosis.