Merlob Syndrome

Inherited disorder characterized by coloboma, microcephaly, porencephaly, and hydronephrosis, in which an affected individual has a head circumference less than 3 standard deviations below the ageand sex-related mean. All affected individuals are mentally retarded.

Primary Autosomal Recessive Microcephaly; MCPH Syndrome.

Approximately 1:250,000 live births. True microcephaly is inherited as an autosomal recessive trait. It is genetically heterogenous, with at least five loci mapped: MCPH1 to chromosome 8p23; MCPH2 to locus 19q13.1-q13.2; MCPH3 at 9q34; MCPH4 at 15q15-q21; and MCPH5 to 1q31, which is a mutant of the ASPM (abnormal spindle-like, microcephaly associated) gene.

Microcephaly with sloping forehead, narrow forehead, and flat occiput. It is associated with mental deficiency and seizures. A small but apparently normally formed brain is the reason for the reduced head circumference.

There are no specific considerations reported. Assessment of severity of seizures and knowledge of treatment.