Below is an instruction from Human. Write a response.
    ### Instruction:
    How to diagnose Tetra-amelia syndrome ?
    ### Response:
    How is tetra-amelia syndrome diagnosed? The diagnosis of tetra-amelia syndrome can be established clinically (based on observed features) and is usually made on a routine prenatal ultrasound. The WNT3 gene has been associated with tetra-amelia syndrome, but the mutation detection frequency (how often a mutation will be found in an affected individual) is unknown because only a limited number of families have been studied.
    