BTOP is characterized by abnormal brain development, seizures, and psychiatric manifestations. It is inherited in an autosomal recessive manner. This means that two healthy parents each carry one copy of FIG4 gene with a variant. When their child inherited both copies with a variant, he will develop BTOP. If both parents carry a defective copy of FIG4 gene, the probability to have an affected child is 25% for each pregnancy. This disease was reported in a single family.
CMT4J is characterized by a severe and early onset form of Charcot-Marie-Tooth disease with sensory and motor neurons involvement. It is also inherited in an autosomal recessive manner.
ALS11 is a milder form of CMT4J. It is characterized by adult-onset motor-neurons findings. It is inherited in an autosomal dominant manner which means that only one copy of the gene must carry the variant for the disease to occur. When someone has a variant causing ALS11, the probability to have an affected child is 50% for each pregnancy. To date, five unrelated individuals have been reported.
YVS is characterized by teeth and bone anomalies, finger anomalies, and severe neurological involvement. It is inherited in an autosomal recessive manner. To date, twenty-five cases from nineteen families have been reported.
FIG4