Cardiovascular malformations and other cardiovascular abnormalities in neurofibromatosis 1.

Although it is well recognized that a peripheral vasculopathy may occur in patients with neurofibromatosis 1 (NF1), it is unclear whether cardiovascular abnormalities are more common. We reviewed the frequency of cardiovascular abnormalities, in particular, cardiovascular malformations (CVMs), among 2322 patients with definite NF1 in the National Neurofibromatosis Foundation International Database from 1991-98. Cardiovascular malformations were reported in 54/2322 (2.3%) of the NF1 patients, only 4 of whom had Watson syndrome or NF1-Noonan syndrome. There was a predominance of Class II "flow" defects [Clark, 1995: Moss and Adams' Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult. p 60-70] (43/54, 80%) among the NF1 patients with CVMs. Pulmonic stenosis, that was present in 25 NF1 patients, and aortic coarctation, that occurred in 5, constitute much larger proportions of all CVMs than expected. Of interest was the paucity of Class I conotruncal defects (2 patients with tetralogy of Fallot), and the absence of atrioventricular canal, anomalous pulmonary venous return, complex single ventricle and laterality defects. Besides the 54 patients with CVMs, there were 27 patients with other cardiac abnormalities (16 with murmur, 5 with mitral valve prolapse, 1 with intracardiac tumor, and 5 with electrocardiogram abnormalities). No patient in this study had hypertrophic cardiomyopathy. There were 16 patients who had a peripheral vascular abnormality without an intracardiac CVM, plus an additional 4 patients among those with a CVM who also had a peripheral vascular abnormality.

Early spontaneous regression of a hypothalamic/chiasmatic mass in neurofibromatosis type 1: MR findings.

A patient with neurofibromatosis type 1 was found to have an enhancing mass in the hypothalamus and in the anterior optic pathway. A 3-month MR study showed a reduction in the size and enhancement of the mass. At a 9-month MR follow-up the mass disappeared and ceased to enhance. This report shows the unusual behaviour of a hypothalamic/chiasmatic mass confirming that in such asymptomatic cases the conservative management can be considered the treatment of choice.

Neurofibromatosis type 1 and precocious puberty.

Since neurofibromatosis type 1 (NF1) is a well known cause of precocious puberty (PP), we reviewed 412 NF1 pediatric patients to evaluate the prevalence of PP, the association with optic pathway tumors (OPT), and other clinical, auxological and hormonal data. Thirty-one of 412 patients had OPT (7.5%), 10/412 PP (2.4%), and in seven of these PP was associated with OPT (7/31, 22.6%). OPT in patients with PP involved the chiasm in four patients, and the optic nerves alone in three patients. The age at the onset of puberty (or better at diagnosis) ranged from 5.2 to 7.5 yr in girls (n=6) and from 7.9 to 8.9 yr in boys (n=4). LHRH agonist therapy was used in only three children because in the others the predicted height at diagnosis was good, treatment was refused or the patients were referred to us too late. The three treated patients attained a final height within the familial range. In the untreated patients the progression of puberty was not too rapid and final height was slightly below the genetic target in four patients; however, three patients had a final height markedly below the familial range. In conclusion, the prevalence of PP is increased in children with NF1, and frequently but not exclusively is associated with OPT. Moreover, sexual precocity does not seem to be necessarily bound to chiasmatic OPT. Treatment seems to be useful in the children with younger age at the onset of puberty or with a progressive decline in predicted final height.

Magnetic resonance findings and ophthalmologic abnormalities are correlated in patients with neurofibromatosis type 1 (NF1).

In subjects with neurofibromatosis type 1 (NF1), we show that a reduction in the visual field is the most sensitive indicator of gliomas along the optic pathway. Therefore, we conclude that a visual field evaluation is the most sensitive clinical test among those evaluated to predict the presence of optic pathway pathology on an MRI examination. These data may contribute to the establishment of more precise guidelines for the evaluation and treatment of children with NF1.

[Genetics of type 1 neurofibromatosis]. / Genetica della neurofibromatosi tipo 1 (NF1).

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder characterised by cafè au lait spots, multiple neurofibromas and Lisch nodules of the iris, with marked variability of expression. The NF1 gene is located at 17q11.2, spans 350 kb genomic DNA and comprises 60 exons encoding a 11-13 kb transcript (Viskochil et al.). Four alternatively spliced NF1 transcripts have been identified and they show differential expression in various tissues. NF1 gene is a member of the tumor suppressor gene family. The protein encoded by NF1, neurofibromin, has a domain homologous to the GTPase activating protein (GAP) family, and downregulates ras activity. Neurofibromin is involved in the control of cellular growth and differentiation and germline mutation analysis has shown that around 82% of all the fully characterised NF1 specific mutations so far predict severe truncation of neurofibromin. The current demand for molecular diagnosis of NF1 is low. Many couples would probably request a prenatal diagnosis if it could predict disease severity. Molecular prediction of disease severity and prognosis may either be very complicated or even impossible. Presymptomatic DNA diagnosis is probably not going to be in huge demand because the clinical diagnosis of NF1 is usually straightforward, even in early childhood. Further knowledge of the gene function may also lead to the development of new therapy for the disease.

Oculo-auriculo-vertebral spectrum in Klinefelter syndrome.

We report a boy with classical 47,XXY Klinefelter syndrome (KS) and oculo-auriculo-vertebral spectrum (OAV). Two patients with KS and OAV were reported previously. Also, the combination of bilateral aplasia of the mandibular ramus and condyle and KS has been documented. The present observation supports the view that the cause of hemifacial microsomia appears heterogeneous and that OAV may be part of the spectrum of craniofacial anomalies associated with KS.

[Extracerebral neoplastic manifestations in neurofibromatosis 1: integrated diagnostic imaging]. / Manifestazioni neoplastiche extracerebrali nella neurofibromatosi tipo 1: diagnostica per immagini integrata.

PURPOSE: To analyze the extracerebral manifestations of type 1 neurofibromatosis (NF-1), with special reference to peripheral nerve tumors. MATERIAL AND METHODS: The findings of 376 NF-1 patients (194 men and 182 women; age range: 0.1-48 years, mean: 8.1) were retrospectively reviewed. The patients had been submitted to abdominopelvic and superficial US and, in case of abnormal US findings or in the presence of symptoms, to CT and/or MRI. In addition, we considered 5 more patients (2 men and 3 women; age range: 50-72 years, mean: 64.4) with incomplete forms of NF-1 diagnosed after the finding of nerve sheath tumors. Biopsy (12 cases), surgery (10 cases), or clinical-instrumental follow-up were the study criteria. RESULTS: In the first group of patients we identified 91 cutaneous, 222 subcutaneous, 11 pendulous and 25 internal neurofibromas. Plexiform neurofibromas were found in the neck (1 case), chest (6 cases), abdomen (16), pelvis (8). We also found 1 benign and 1 malignant Schwannomas, 2 nerve sheath fibrosarcomas, 1 dopamine-producing sympatoma and 1 spermacytoma. As for the second group of patients, we had 2 Schwannomas, 1 pulmonary neurofibroma, and 2 multiple plexiform neurofibromas. The neurofibromas exhibited homogeneous US hypoechogenicity or slight echogenicity, with little contrast enhancement at CT. MR showed peripheral hyperintensity and central hypointensity on T2-weighted sequences and marked contrast enhancement after gadolinium, sometimes with mostly central uptake. The plexiform neurofibromas, which are typical of NF-1, had poorly-defined or infiltrating margins, with similar findings to the previous ones but sometimes with less homogeneous patterns at both US and CT. The Schwannomas, which are a less common finding in NF-1, exhibited different features at MRI and CT, namely pseudo-liquid or solid-inhomogeneous patterns with irregular and inhomogeneous contrast enhancement relative to the Antoni A/B tumor component. In the malignant lesions we observed infiltrating patterns, with irregular and inhomogeneous contrast enhancement, arranged asymmetrically relative to the contralateral lesion. CONCLUSIONS: Extra-axial neoplasms are a frequent finding in NF-1. Despite the extremely variable appearances of some lesions (particularly Schwannomas), the typical plexiform neurofibroma exhibits characteristic patterns. The diagnosis of malignancy often requires bioptic confirmation.