Any autosomal recessive primary microcephaly in which the cause of the disease is a mutation in the MCPH1 gene. The disease is Monarch Disease Ontology id MONDO_0009617 (microcephaly 1, primary, autosomal recessive). Also known as: MCPH1 autosomal recessive primary microcephaly, autosomal recessive primary microcephaly caused by mutation in MCPH1.