Pallister-Killian Syndrome is an uncommon genetic affection which incidence is approximately 1/25,000 patients. It is caused by the presence of mosaic tetrasomy of short arm of chromosome 12 (12p) [2,3]. Its genetic inheritance remains unknown, being notified cases for the most part sporadic onset. This disease is a multisystem disorder characterized by a dysmorphic phenotype which includes rounded forehead, broad nasal bridge and short nose, hypertelorism, wide mouth with thin upper lip and long tongue, and low-set ears. It is distinguished by sparse hair (principally temporal alopecia), pigmentation and multiple organic disorders such as diaphragmatic herniation, heart, renal, genital or palate abnormalities. Some cases may also include skeletal deformities: supernumerary fingers or rhizomelic limbs. This syndrome also includes hypotonia in early childhood, developmental delay, intellectual disabilities, seizures, hearing impairment and sight issues.

We report a case of a female 36 weeks gestation preterm who was diagnosed in early neonatal period. It was the second gestation of a non-consanguineous parents. This fact might be important because it reduced the possibility of recessive inheritance diseases. The pregnancy was controlled. It presented polyhydramnios which cause remained unknown after a complete test. Routine sonography showed a 15.9 mm left pyelocaliceal ectasia, a small renal pelvis dilation which remained alike until birth. There were no other abnormalities seen. It was a cesarean birth with 8/9 Apgar score. At the operating room she immediately initiated acute respiratory distress, so she was admitted to the Neonatal Unit. From the moment she was born, it stood out the presence of a dysmorphic phenotype with a wide forehead, frontotemporal alopecia, broad and depressed nasal bridge, ascending crosswise small palpebral edges, hypertelorism, downwards mouth corners and rhizomelic upper limbs