The shortest of the short: pericentrin mutations and beyond.

Microcephalic or Majewski's osteodysplastic primordial dwarfism type II (MOPD II) represents the most common type of primordial dwarfism. Adult height is typically about one meter and short stature is becoming mildly disproportionate over time with mild skeletal anomalies. Mental development is usually borderline or within the low normal range but cerebrovascular events that are common in childhood can result in significant cognitive impairment and cerebral palsy. Despite cerebrovascular insults, cardiomyopathy and early onset type 2 diabetes contribute to early mortality and morbidity. Common minor clinical features are truncal obesity, high pitched voice, microdontia and pigmentary changes. MOPD II is caused by autosomal recessive loss of function mutations in the PCNT gene encoding for a key centrosomal protein. There is clinical overlap with the so called Seckel syndrome, a heterogeneous group of entities with at least four different gene loci known to date.