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The Condition


Rhombencephalosynapsis (RS) is a rare cerebellar malformation, first described by Obersteiner, in 1914 (a postmortem description of a 28-year-old man), and it is characterized by the absence or hypogenesis of the vermis and the midline fusion of the cerebellar hemispheres into a single mass. Unlike other vermian maldevelopment syndromes (such as Dandy-Walker complex, Joubert syndrome or tectocerebellar dysraphia), there is no disconnection of cerebellar hemispheres, rather they continue seamlessly through the midline. Some authors believe that this anomaly is not secondary to a primary maldevelopment of the vermis, but rather, results from a primary failure of vermian differentiation. Thus, there would be undivided hemispheres instead of fused ones, possibly due to defective gene expression in early patterning centers of the brain. The pathogenesis is related to a disturbed development of the cerebellum between 28 and 41 days of gestation. However, to this date, true causative factors remain controversial.

Mendonca JL, Natal MR, Viana SL, Coimbra PP, Viana MA, Matsumine M. Rhombencephalosynapsis: CT and MRI findings. Neurol India 2004;52:118-20


There have only been about 5o reported cases of Rhombencephalosynapsis since the first known one in 1914. Until the use of the MRI in 1991, only a few cases were reported. Most doctors, including specialists, have never heard of this condition.

Many people with Rhombencephalosynapsis have normal intelligence. One doctor explained that the cerebellum is a redundant tissue, meaning that several parts do the same thing. He also said things that are usually subconscious could be learned.

Some physical features that seem to be exhibited are irregular hair growth, short stature, inability to gain weight and low set ears.

Gomez-Lopez-Hernandez Syndrome is the only syndrome associated with RS at this time. Gomez-Lopez-Hernandez syndrome consists of RS, alopecia, and trigeminal anesthesia. Many other related conditions and traits have been reported.

  Two Head Graphic
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