CASE PRESENTATION
A six-year-old boy, an only child of a healthy and non-consanguineous couple, presented with dysmorphic facial features—arched eyebrows, downward slanting eyes, myopathic face, hypertelorism, broad nasal root, strabismus, low set ears and micrognathia, multiple café-au-lait spots (> 50), a cNF, and delayed psychomotor development from the neonatal period.
During follow-up, there was an increase in the number of cNF (>20) and development of numerous neurofibromas in the nerve pathways, including the intercostal and pelvic plexus. He also presented with a pNF that affected the upper limb when he was seven years old. At four years of age, he had been diagnosed with a Lisch nodule in his right eye. The General Intelligence Assessment results for cognitive ability was 66%, validating the diagnosis of mental retardation.
Brain magnetic resonance imaging demonstrated small hamartomas in the globus pallidus, thalamus, periaqueductal gray, splenium of the corpus callosum (right), deep ipsilateral cerebellar hemisphere, and pons, no mass effect. Abdominal computed tomography revealed a 89 mm × 56 mm retroperitoneal mass, affecting the great visceral vessels, but with no occlusion, and exerting a mass effect on the adjacent structures. For the etiological diagnosis, sequencing and Multiplex Ligation-dependent Probe Amplification analysis of the NF1 gene was carried out that revealed a heterozygous deletion of the complete coding sequence of the gene.
Chromosomal microarray test revealed a submicroscopic deletion on the long arm of chromosome 17 (band 17q11.2). This was an uncommon type 2 deletion of 1.2 Mb that was generated by non-allelic homologous recombination, with breakpoints located within the SUZ12 gene and its SUZ12P pseudogene.