De La Chapelle Syndrome

De La Chapelle Syndrome (also known as XX Male Syndrome or 46, XX Testicular Disorder) is an intersex variation that effects one in every 20,000 AMAB or CTM births in which an individual has müllerian chromosomes (XX chromosomes) however they have a wolffian appearance outwardly.

Most with this variation have small testicles or a missing testicle or a urethra opening that is on a unusual spot of the genitals (hypospadias.) On rare occasion, one with this variation may have ambiguous genitals. Because of this, they may have AMAB Hypogonadism.

Many with this variation tend to be shorter than average and infertile, however with testosterone treatments (HRT) one may have a higher chance at a more natural flow of growth during puberty.

A similar intersex variation is SERKAL Syndrome.

Causes
In about 80% of individuals with De La Chapelle Syndrome, the variation results from an abnormal exchange of genetic material between chromosomes while they were forming in the uterus, which causes the individual to have no Y chromosomes, or only partial Y chromosomes.