Craniopagus twins are conjoined twins that are fused at the cranium. The union may occur on any portion of the cranium, but does not primarily involve either the face or the foramen magnum; their brains are usually separate, but they may share some brain tissue. Conjoined twins are genetically identical and always share the same sex. The thorax and abdomen are separate and each twin has its own umbilicus and umbilical cord.The condition is extremely rare, with an incidence of approximately 1 in 2.5 million live births. An estimated 50 craniopagus twins born around the world every year as of 2021, with only 15 twins surviving beyond the first 30 days of life. Relatively few craniopagus twins survive the perinatal period; approximately 40% of conjoined twins are stillborn and an additional 33% die within the immediate perinatal period, usually from organ abnormalities and failure.However, 25% of craniopagus twins survive and may be considered for a surgical separation; several such attempts occur yearly worldwide. Advances in neuroimaging, neuroanesthesia, and neurosurgery have proven that a successful outcome is possible. Among all conjoined twins, craniopagus twins account for a mere 2% to 6%. Classification
The first classification system was developed by OConnell in 1976, where craniopagus twins were classified as total and partial. In the former, twins shared an "extensive surface area with widely connected cranial cavities", while in the latter, only a "limited, superficial surface area" was connected.In 2006, Stone and Goodrich came up with a more nuanced classification system, which is the "most commonly used" system.
Prognosis
The prognosis of this sub-type of MD indicates that the affected individual may eventually have feeding difficulties. Surgery, at some point, might be an option for scoliosis.Scoliosis, which is a sideways curve of the persons vertebrate, is determined by a variety of factors, including the degree (mild or severe), in which case if possible a brace might be used by the individual. Research
In terms of possible research for Ullrich congenital muscular dystrophy one source indicates that cyclosporine A might be of benefit to individuals with this CMD type.According to a review by Bernardi, et al., cyclosporin A (CsA) used to treat collagen VI muscular dystrophies demonstrates a normalization of mitochondrial reaction to rotenone. See also
Muscular dystrophy
Congenital muscular dystrophy

References
Further reading
Ph.D, Evelyn B. Kelly (2013-01-07). Encyclopedia of Human Genetics and Disease [2 volumes]. ABC-CLIO. ISBN 9780313387142. Carakushansky, Gerson; Ribeiro, Marcia Gonçalves; Kahn, Evelyn (2011). "Moderately progressive Ullrich congenital muscular dystrophy". Jornal de Pediatria. 88 (1): 93–96. doi:10.2223/JPED.2112. ISSN 0021-7557. PMID 22016142. "National Guideline Clearinghouse | Evidence-based guideline summary: evaluation, diagnosis, and management of congenital muscular dystrophy: report of the Guideline Development Subcommittee of the American Academy of Neurology and the Practice Issues Review Panel of the American Association of Neuromuscular and Electrodiagnostic Medicine". www.guideline.gov. Archived from the original on 2016-04-08. Retrieved 2016-05-12. Hicks, D.; Lampe, A. K.; Laval, S. H.; Allamand, V.; Jimenez-Mallebrera, C.; Walter, M. C.; Muntoni, F.; Quijano-Roy, S.; Richard, P.; Straub, V.; Lochmuller, H.; Bushby, K. M. D. (16 November 2008).