Parents

Chudley-McCullough syndrome (CMCS) is a rare genetic disorder that can affect both males and females in equal numbers. All individuals with Chudley-McCullough syndrome have congenital or childhood-onset hearing loss and some changes in the brain seen on brain imaging. Every ethnicity may be affected. The features of CMCS can be appreciated at or after birth, but some signs may even be visible prenatally during an ultrasound examination.

Individuals with CMCS can be born with profound sensorineural hearing loss (deafness) or develop hearing loss early in childhood. Psychomotor development is normal in most, but mild developmental delay has been observed. When hearing loss is managed early, most individuals have minor or no impairment of speech, motor and cognitive development, despite the presence of brain malformations. Seizures, while not commonly associated, have been reported.

CMCS is present in individuals with two disease-causing variants, one in each copy of the GPSM2 gene. Most often, one variant is inherited from each parent, who are carriers for the condition but are not themselves affected. This is called being a healthy carrier. Both parents of a child with CMCS are usually carriers, and have a 25% risk of having a child with the condition in every pregnancy. A personalized risk assessment can be performed in a genetic counseling session when planning for a pregnancy. Prenatal and preimplantation genetic testing for CMCS is also possible.