Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) is a rare autosomal recessive genetic disorder characterized by a slowly progressing abnormality in retinal vascular permeability and retinal telangiectasia, along with neurological impairment, skeletal defects, movement disorders, epileptic seizures, osteopenia with frequent brain fractures, and postnatal growth failure. The retinal telangiectasia progresses from yellow white raised exudate patches under normal vessels to retinal detachment, cataract, glaucoma, pthisis bulbi, and, ultimately, blindness. Diagnosis of the condition depends upon brain imaging studies, which should show extensive brain calcifications, with a progressive leukoencephalopathy. CRMCC is also known as Coats Plus syndrome, due to its similarity with Coats disease, another disorder characterized by a similar form of retinal telangiectasia, but without the other features of CRMCC.
Rajab et al. (2009) studied two Omani families from the same tribal unit, both of which had chidren affected with a similar disorder involving postanatal growth failure and brain calcifications. In the two familie, there were eight affected children (six girls) with ages ranging from 7-years to 28-years at the time of examination. All patients were born as results of full term normal deliveries, with normal birth weights. In these patients, the disorder varied in intensity, but was principally characterized by delayed attainment of neurological milestones, poor academic progress, cognitive difficulties of varying magnitude, dysarthria, and poor motor coordination. No dysmorphic features were seen in any of the patients. In addition, height, weight, and OFC were significantly less than the Omani average for all patients, indicating postnatal growth failure. One of the children developed hydrocephalus, which was managed by inserting a VP shunt. Imaging studies of the brain revealed cerebral calcifications and microcephaly. The calcifications involved the cerebral cortex, particularly the gray-white borders in the depths of the sulci. No vascular abnormalities were seen in the MR Angiogram when done in the patients. Rajab et al. (2009) compared the features of this syndrome to other known forms of brain calcinosis and concluded that CRMCC was the best fit for the family, considering the mild to moderate congnitive impairment, mild motor impairment, growth deficiency, osteopenia, and the distribution of intracerebral calcifications. However, none of the patients showed any visual impairment, and neither did any of them have cerebral cysts, or leukoencephalopathy; other characteristics of CRMCC. Rajab et al. (2009) were also able to map the disorder in these families using recombination frequency mapping to a large 15 cM region on chromosome 2q. However, this region was not known to contain any genes involved in calcium homeostasis or exonucleases.