Neurofibromatosis-Noonan syndrome and acute lymphoblastic leukemia: a report of two cases

Portraying the full picture of Neurofibromatosis-Noonan syndrome: a systematic review of literature

BACKGROUND AND AIMS

Neurofibromatosis-Noonan syndrome (NFNS) is an extremely rare genetic entity combining the clinical phenotype of two conditions: neurofibromatosis type 1 syndrome (NF1) and Noonan syndrome (NS). Nevertheless, many inconsistencies reside in our understanding of this condition, mainly its clinical features and genetic background. Through this systematic review, we aim to shed light on the epidemiological features, the broad clinical spectrum, the underlying genetic defects and the associated comorbidities of NFNS.

METHODS

Medline, Scopus and Google Scholar were searched for publications on the clinical and genetic features of patients with NFNS. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed and the study protocol was registered in PROSPERO.

RESULTS

Of 951 records screened, 42 were eligible. The mean age at diagnosis was 14.7 years ranging from 0 to 69 years. As for the circumstance of discovery of NFNS, it was dominated by family investigation followed by neurofibromas, facial dysmorphia and short stature (SS). Prematurity was noted in 40.9% of cases. The hallmark features of NFNS at diagnosis were 'café au lait' macules, typical facial dysmorphia of NS, postnatal SS, pectus abnormalities, broad neck and lentigines. Macrocephaly, scoliosis and cardiopathies occurred in 26%, 42.4% and 36.9% of cases, respectively. Tumours were found in 18.4% of cases. As for the genetic foundation of NFNS, NF1 gene mutations were depicted in 87.5% of individuals.

CONCLUSIONS

Based on our findings, we emphasise on the importance of searching for NS features in patients with NF1 since the prognosis, comorbidities and consequently management could be altered.

PROSPERO REGISTRATION NUMBER

42024522238.

Neurofibromatosis-Noonan syndrome and growth deficiency in an Iranian girl due to a pathogenic variant in NF1 gene

BACKGROUND

Mutations in NF1 gene could cause allelic disorders with clinical spectrum of Neurofibromatosis type 1 to Noonan syndrome. Here, a 7-year-old Iranian girl is described with Neurofibromatosis-Noonan syndrome due to a pathogenic variant in NF1 gene.

METHODS

Clinical evaluations were performed along with genetic testing using whole exome sequencing (WES). The variant analysis including pathogenicity prediction was also done using bioinformatics tools.

RESULTS

The chief compliant of the patient was short stature and lack of proper weight gain. Other symptoms were developmental delay, learning disability, inadequate speech skill, broad forehead, hypertelorism, and epicanthal folds, low set ears and webbed neck. A small deletion, c.4375-4377delGAA, was found in NF1 gene using WES. This variant was classified as pathogenic according to ACMG.

CONCLUSIONS

NF1 variants may show variable phenotypes among the patients; identifying such variants is helpful in therapeutic management of the disease. WES is considered as an appropriate test to diagnose Neurofibromatosis-Noonan syndrome.

The genomic landscape of hypodiploid acute lymphoblastic leukemia

The genetic basis of hypodiploid acute lymphoblastic leukemia (ALL), a subtype of ALL characterized by aneuploidy and poor outcome, is unknown. Genomic profiling of 124 hypodiploid ALL cases, including whole-genome and exome sequencing of 40 cases, identified two subtypes that differ in the severity of aneuploidy, transcriptional profiles and submicroscopic genetic alterations. Near-haploid ALL with 24-31 chromosomes harbor alterations targeting receptor tyrosine kinase signaling and Ras signaling (71%) and the lymphoid transcription factor gene IKZF3 (encoding AIOLOS; 13%). In contrast, low-hypodiploid ALL with 32-39 chromosomes are characterized by alterations in TP53 (91.2%) that are commonly present in nontumor cells, IKZF2 (encoding HELIOS; 53%) and RB1 (41%). Both near-haploid and low-hypodiploid leukemic cells show activation of Ras-signaling and phosphoinositide 3-kinase (PI3K)-signaling pathways and are sensitive to PI3K inhibitors, indicating that these drugs should be explored as a new therapeutic strategy for this aggressive form of leukemia.

Juvenile papillomatosis of the breast in a male infant with Noonan syndrome, café au lait spots, and family history of breast carcinoma

Juvenile papillomatosis (JP) of the breast is a rare condition, usually affecting women under 30 years of age. Although this is considered a benign lesion, follow-up is recommended for the patient and family since there is an association with a family history of breast carcinoma and increased risk of development of breast carcinoma. We report an infant with JP, Noonan syndrome (NS), café au lait spots, and family history of breast carcinoma. Seven previously reported cases of JP in males exist, two occurring in infants. The association between JP and NS has not been previously reported.

PTPN11 mutations in pediatric patients with acute myeloid leukemia: results from the Children's Cancer Group

The PTPN11 gene encodes SHP-2, a nonreceptor protein tyrosine phosphatase that relays signals from activated growth factor receptors to p21(ras) (Ras) and other signaling molecules. Somatic PTPN11 mutations are common in patients with juvenile myelomonocytic leukemia (JMML) and have been reported in some other hematologic malignancies. We analyzed specimens from 278 pediatric patients with acute myelogenous leukemia (AML) who were enrolled on Children's Cancer Group trials 2941 and 2961 for PTPN11 mutations. Missense mutations of PTPN11 were detected in 11 (4%) of these samples. None of these patients had mutations in NRAS; however, one patient had evidence of a FLT3 alteration. Four of the patients with PTPN11 mutations (36%) were boys with French-American-British (FAB) morphology M5 AML (P=0.012). Patients with mutations also presented with elevated white blood cell counts. There was no difference in clinical outcome for patients with and without PTPN11 mutations. These characteristics identify a subset of pediatric AML with PTPN11 mutations that share clinical and biologic features with JMML.