Genotype-phenotype Association In A Boy With Neurofibromatosis Type 1

Introdcution: Neurofibromatosis type 1 (NF1), is the most common form of Neurofibromatosis. Clinical characteristics include: café-au-lait spots, inguinal and axillary ephelides, multiple neurofibromas and Lisch nodules. Is an autosomal dominant disorder, with extreme clinical variability. The gene complexity and the diversity of mutations in NF1 gene make the genotype-phenotype correlations very difficult.

Case Presentation: We describe a case of a 9-years-old boy, first child of a healthy and unrelated couple, who had dismorphic facial features, multiple café-au-lait spots, and delayed psychomotor development since first year of life.

At eight months of age, neurofibroma was detected, and molecular study was requested confirming the presence of mutation in the NF1 gene.

During follow-up, there was an increase in the number of cutaneous neurofibromas and development of numerous neurofibromas in nerve pathways, including intercostal, pelvic nerve plexus, thigh roots, as well as plexiform neurofibroma affecting the upper limb. He also presented intellectual impairment and Lisch nodule in the left eye.

Cerebral magnetic resonance showed small hamartomas in the pale globes, thalamus, peri-aquedutal region, splenius of the corpus callosum on the right side and at the ipsilateral deep slope of the cerebellar hemisphere and protuberance, with no mass effect.

The abdominal study revealed the presence of a retroperitoneal mass, measuring 95x68 mm, involving the large visceral vessels, but without occluding them and exerting mass effect on the adjacent structures. This mass still`s under study.

Array-CGH analysis revealed microdeletion of 1.29 Mb in the long arm of chromosome 17 (band 17q11.2).

Conclusion: Although many different mutations associated with neurofibromatosis, have been described, information about genotype-phenotype correlations are still limited. Authors pretend to emphasize the association of deletions involving NF1 gene and a more severe phenotype, as can be seen in our patient.