Subcortical band heterotopia – Genetics Home Reference


The inheritance pattern of subcortical band heterotopia depends on its genetic cause.

When subcortical band heterotopia is caused by mutations in the DCX gene, it is inherited in an X-linked pattern. The DCX gene is located on the X chromosome, which is one of the two sex chromosomes. In females, who have two copies of the X chromosome, one altered copy of the gene in each cell can lead to the condition, sometimes with less severe symptoms than affected males. In males, who have only one X chromosome, a mutation in the only copy of the gene in each cell usually causes a more severe condition called isolated lissencephaly sequence (ILS). Most males with subcortical band heterotopia have a DCX gene mutation that is not inherited and is present in only some of the body’s cells, a situation known as mosaicism. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

When subcortical band heterotopia is caused by a PAFAH1B1 gene mutation, it is generally not inherited but arises from a mutation in the body’s cells that occurs after conception, which leads to mosaicism. This alteration is called a somatic mutation. PAFAH1B1 gene mutations that occur in all of the body’s cells (germline mutations) usually cause ILS.

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