Opitz G/BBB Syndrome

Opitz G/BBB syndrome is a condition that - in some cases - may be considered an intersex condition, although many would say it causes intersex conditions rather than being one in of itself. Opitz G/BBB syndrome is thought to affect 1 in 10,000 to 50,000 CTM or AMAB individuals, although, according to proffessionals, it is likely that this condition is underdiagnosed.

This condition can cause a missing or undescended testicle, hypospadias, an underdeveloped scrotum, and/or a scrotum divided into two lobes. This may cause urinal issues.

This condition often comes with defects in the voice box, windpipe, or esophagus which, in many cases, causes breathing and swallowing abnormalities that can, in some cases, be life threatening. This condition often comes with distinct facial features, such as a prominent forehead, a thin upper lip, low ears, and a flat nasal bridge.

Studies have shown that 50% of individuals with this condition have autism and other mental disabilities. This often causes a delay in speech and motor skills, as well as learning disabilities. 50% also tend to have a cleft lip or cleft palate. In some rarer cases, heart defects, anal obstruction, and/or absencies between the left and right side of the brain are found.

Causes
This condition can be caused by two things; mutations in the MID1 gene (a gene that provides instructions for making midline-1, which is a protein that binds microtubules) or changes/mutations in chromosome 22, which may include the entire deletion of the chromosome in of itself.

There are some rare cases where niether of these reasonings apply, and it is unknown how those without these two causes gains this condition.

Resources

 * https://medlineplus.gov/genetics/condition/opitz-g-bbb-syndrome/#frequency
 * https://en.wikipedia.org/wiki/Opitz_G/BBB_syndrome