MDC1 and Abnormal sperm morphology: Finally, we identified two heterozygous nonsense variants (c.472C>T; p.(Gln158*) in Exon 3 and c.2134C>T; p.(Gln712*) in Exon 7) in Mediator of DNA Damage Checkpoint 1 (MDC1) in patient AUS11, who suffered from mild oligozoospermia combined with astheno-teratozoospermia (Table III).