This is what Epstein says about Micro syndrome and microcephaly:
'Warburg Micro syndrome (OMIM 60018) and Martsolf syndrome (OMIM 21270) are autosomal recessive neurodevelopmental disorders that may result from the dysregulation of the Rab3 pathway. Inactivating germline mutations....Micro syndrome is a severe disorder characterized by ocular (microphthalmos, microcornea, congenital cataracts, optic atrophy; neurodevelopmental microcephaly, cortical gyral abnormalities -- polymicrogyria, hypoplasia of the corpus callosum, severe learning disability, spastic cerebral palsy) and endrocrine abnormalities. Martsolf has an overlapping but less severe phenotype.'
(Epstein, Inborn Errors of Development, Ch. 146 RAB3GAP1 and RAB3GAP2 and Warburg Micro and Martsolf Syndromes)
'Warburg Micro syndrome (OMIM 60018) and Martsolf syndrome (OMIM 21270) are autosomal recessive neurodevelopmental disorders that may result from the dysregulation of the Rab3 pathway. Inactivating germline mutations....Micro syndrome is a severe disorder characterized by ocular (microphthalmos, microcornea, congenital cataracts, optic atrophy; neurodevelopmental microcephaly, cortical gyral abnormalities -- polymicrogyria, hypoplasia of the corpus callosum, severe learning disability, spastic cerebral palsy) and endrocrine abnormalities. Martsolf has an overlapping but less severe phenotype.'
(Epstein, Inborn Errors of Development, Ch. 146 RAB3GAP1 and RAB3GAP2 and Warburg Micro and Martsolf Syndromes)