microcephaly vs nanocephaly

microcephaly and nanocephaly both are nouns.

Word	Noun	Adjective	Verb	Adverb
microcephaly	Yes	No	No	No
nanocephaly	Yes	No	No	No

As nouns, microcephaly and nanocephaly are synonyms defined as:

microcephaly and nanocephaly: an abnormally small head and underdeveloped brain

Other synonyms of microcephaly include microcephalus.

microcephaly (noun)	nanocephaly (noun)
an abnormally small head and underdeveloped brain	an abnormally small head and underdeveloped brain