Phenotypic Spectrum of Haploinsufficiency: Two Additional Cases and Review of the Literature.

The (nuclear factor I/A) gene encodes for a transcription factor belonging to the nuclear factor I family and has key roles in various embryonic differentiation pathways. In humans, is the major contributor to the phenotypic traits of "Chromosome 1p32p31 deletion syndrome". We report on two new cases with deletions involving without any other pathogenic protein-coding gene alterations. A cohort of 24 patients with haploinsufficiency as the sole anomaly was selected by reviewing the literature and public databases in order to analyze all clinical features reported and their relative frequencies. This process was useful because it provided an overall picture of the phenotypic outcome of haploinsufficiency and helped to define a cluster of phenotypic traits that can facilitate clinicians in identifying affected patients. haploinsufficiency can be suspected by a careful observation of the dysmorphisms (macrocephaly, craniofacial, and first-finger anomalies), and this potential diagnosis is strengthened by the presence of intellectual and developmental disabilities or other neurodevelopmental disorders. Further clues of haploinsufficiency can be provided by instrumental tests such as MRI and kidney urinary tract ultrasound and confirmed by genetic testing.