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Debrisoquine hydroxylase gene polymorphism in neurofibromatosis type 1.

Cytochrome P450 CYP2D6 polymorphism is an autosomal recessive trait leading to impaired sparteine/ debrisoquine metabolism in 5-10% of the Caucasian population. Previous studies have associated affected individuals (poor metabolizers = PM) with susceptibility to bladder cancer and various forms of leukemia. In many other cancer forms, the data remain contradictory. A PCR assay allows the convenient screening of about 90% of known mutations resulting in the PM phenotype. Since in patients with neurofibromatosis type 2, we had observed a significantly increased rate of CYP2D6 mutations leading to PM and apparently predisposing for NF2, we extended our investigation to tumor and peripheral blood samples obtained from NF1 patients. Although the number of cases investigated remains low, the study indicated that during tumor formation no changes occurred at the mutational hot spot within the CYP2D6 sequence. Moreover, no loss of heterozygosity was notable. However, the frequency of the mutated allele in the NF1 individuals is comparable to that of neurofibromatosis type 2 and above that observed in breast and colon cancer, or meningiomas.

Adolescent↗

[Neurofibromatosis].

Neurofibromatoses regroup at least two different autosomal dominant disorders, neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). NF1 gene and NF2 genes have been respectively localized on chromosomes 17 and 22. NF1 represents 95% of neurofibromatoses cases. Its incidence is 1 for 3,500 newborns, its prevalence 1 for 4,500. NF1 is characterized by its cutaneous manifestations, café au lait spots, lentigines and neurofibromas. NF2 incidence is 1 for 33,000-40,000 newborns. NF2 is characterized by bilateral vestibular schwannomas (former acoustic neurinomas) and other tumors of the central nervous system. The hallmark of schwannomatosis (neurilemmomatosis) is multiple cutaneous or subcutaneous schwannomas without vestibular schwannomas. Different neurofibromatoses are characterized by different prognosis, complications, and genetic counseling. Multidisciplinary centers with trained physicians are ideal structures for management of neurofibromatoses patients.

Diagnosis, Differential↗

Neurofibromatosis and early onset of cancers in hMLH1-deficient children.

Hereditary nonpolyposis colon cancer is a common hereditary disorder caused by the germ-line mutations of DNA mismatch repair (MMR) genes, especially hMLH1 and hMSH2. We report here the first identification of human compounds with a homozygous inactivation of a MMR gene. In a typical hereditary nonpolyposis colon cancer family, MMR-deficient children conceived from matings between heterozygotes for a hMLH1 deleterious mutation exhibited clinical features of de novo neurofibromatosis type I and early onset of extracolonic cancers. This observation demonstrates that MMR deficiency is compatible with human development but may lead to mutations during embryogenesis. On the basis of clinical symptoms observed in MMR-deficient children, we speculate that the neurofibromatosis type 1 gene is a preferential target for such alterations.

Adaptor Proteins, Signal Transducing↗

A new sign of neurofibromatosis on magnetic resonance imaging of children.

Ten pediatric patients with clinically proved neurofibromatosis underwent magnetic resonance imaging of the brain. Seven of these patients had lesions of increased signal intensity on T2-weighted images in the globus pallidus, brain stem, or cerebellar white matter. The lesions did not correlate with results of the neurologic examination or with developmental status. These abnormalities most likely represent hamartomas and should be recognized as part of the diagnostic spectrum of neurofibromatosis.

Adolescent↗

Neurofibromatosis type 1.

Neurofibromatosis (NF) has perhaps been the most notorious of the neurocutaneous disorders. Both Quasimoto of Victor Hugo's The Hunchback of Notre Dame and John Merrick, known as the Elephant Man (who subsequently has been more properly classified as having Proteus syndrome, a quite different disorder), are 2 infamous examples that have shaped many popular misconceptions about this disease. Neurofibromatosis is now understood as a hamartomatous disorder on the basis of molecular genetic studies. Studies on NF have been pivotal to understanding the functions of oncogenes in tumorigenesis.

History, 16th Century↗

Orbital neurofibromatosis: involvement of the orbital floor.

Neurofibromatosis has been reported to involve the eye and orbit by causing irregularities of the sphenoid and other facial bones and enlargement of the foramina. To our knowledge, abnormalities of the orbital floor, however, have not been attributed to this disease in the literature until now. Two patients with neurofibromatosis had orbital floor involvement. Multiple neurofibromas eroding the orbital floor threatened vision in one patient. The other case, seen after trauma, had a condition simulating that of a blow-out fracture. Diagnostic workup with adequate roentgenography, especially tomography, helped to establish the diagnosis. We believe this is of importance in modifying the surgical approach, obviating the need for surgical intervention at times.

Female↗

Café-au-lait spots of the fundus in neurofibromatosis.

Mild pigmentary changes found in the fundi of two patients with neurofibromatosis, resembled café-au-lait spots homologous with skin manifestations of the disease. In one, associated retinal hamartomas were present. The café-au-lait lesions were clinically distinct from previously reported uveal melanomas and may represent a hitherto unrecognized sign of ocular neurofibromatosis.

Adult↗

Orbital optic glioma in neurofibromatosis. Magnetic resonance diagnosis of perineural arachnoidal gliomatosis.

In a patient with neurofibromatosis and orbital optic glioma, T2-weighted axial magnetic resonance images showed a fusiform area of high signal intensity with a central linear core of lower signal intensity. Computed tomographic images did not show a corresponding variation in tumor density. Histopathologic examination of the tumor revealed dense, circumferential, perineural glial proliferation. This "arachnoidal gliomatosis" is a feature of orbital optic gliomas in neurofibromatosis and, in our magnetic resonance scans, accurately corresponded with the region of high signal intensity within the tumor.

Arachnoid↗

Thoracic coarctation associated with neurofibromatosis.

A child with neurofibromatosis and hypertension also demonstrated renal artery stenosis, the most common cause of hypertension in children with neurofibromatosis; abdominal coarctation, which has previously been described; and thoracic coarctation, which to our knowledge, has not been previously reported. Rib notching may appear in patients with uncomplicated nueorfibromatosis, but the possibility of associated thoracic coarctation must also be considered in these patients.

Adolescent↗

Neurofibromatosis with congenital glaucoma and buphthalmos in a newborn.

A newborn infant with unilateral eyelid swelling, proptosis, and glaucoma is described. The diagnosis of congenital neurofibromatosis was made on the basis of a positive family history and by inspection of the patient. It is suggested that this clinical problem is more common at birth than generally recognized. Clinicians should be aware that congenital glaucoma secondary to neurofibromatosis is a distinct entity that can manifest itself in the newborn period.

Female↗

Ullrich-Turner syndrome and neurofibromatosis-1.

There is a well-known association between neurofibromatosis-1 (NF1) and Noonan syndrome-like manifestations, including short stature, short broad neck, and hypertelorism. These anomalies are thought to be due to variable expression of the NF1 gene. We report on two girls with NF1 who were found to have the Ullrich-Turner syndrome. Case 1, a 12-year-old white girl, was followed in a Neurofibromatosis Clinic because of multiple café-au-lait spots and a family history of NF1 in her mother and sister. On examination, she had short stature, hypertelorism, and short neck with low posterior hairline. Karyotype was 86% 46,XY/14% 45,X. Case 2, the first child of a woman with NF1, presented at birth with lymphedema of hands and feet and a short broad neck. Karyotype was 45,X. At age 23 months she was short, had epicanthic folds, hypertelorism, narrow palate, right simian crease, 19 café-au-lait spots, and axillary freckling. We conclude that chromosome studies should be performed in girls with NF1 who have short stature and Noonan- or Ullrich-Turner-like findings. Dilemmas raised by the dual diagnoses of NF1 and Ullrich-Turner syndrome include potential risks of growth hormone therapy and estrogen replacement therapy.

Brain Neoplasms↗

Descriptive analysis of tibial pseudarthrosis in patients with neurofibromatosis 1.

Five percent of individuals with neurofibromatosis type 1 (NF1) present with congenital long bone pseudarthrosis (PA). In large series, 50-80% of patients with congenital long bone PA also have NF1. Very little information exists on the natural history and pathogenesis of PA in NF1. This report is a descriptive analysis of a large series of patients with NF1 and tibial bowing or PA. Study A is a case-control study using the National Neurofibromatosis Foundation International Database (NNFFID). Eighty-five patients with PA were compared to a control group from the same database. There was a statistically significant male predominance of NF1 cases with PA (54 males to 31 females), compared to controls (85 males to 87 females) (chi2 = 4.0, P = 0.046, using a two-tailed test with Yates' correction). There was no significant difference in the clinical presentation of NF1 manifestations in NF1 patients with PA than in NF1 patients without PA. Of the affected individuals with PA, there were 24 de novo cases and 21 familial cases (9 through maternal and 12 through paternal inheritance). Questions that could not be answered by Study A were addressed by a partially overlapping case-series report, Study B, in which data on 75 cases ascertained through questionnaires completed by NF center directors were collected. From Study B we determined that half of the patients who had a fracture sustained it before age 2, and approximately 16% of the pseudarthrosis patients had an amputation. Our data indicate a male predominance and no parent-of-origin effect. Male gender may be a susceptibility factor for pseudarthrosis in NF1.

Adolescent↗

Neurofibromatosis type 1 growth charts.

Growth abnormalities such as macrocephaly and short stature have been described and are considered a consistent finding in neurofibromatosis type 1 (NF1), one of the most common autosomal dominant disorders in man. We present here a clinical study on the growth profile of a sample of NF1 patients collected through a population-based registry that covers three contiguous regions of North-East Italy (NEI-NF Registry). Auxometric traits of 528 NF1 patients have been measured with the aim of drawing growth charts for height, weight, and head circumference (OFC). Height velocity charts were based on a subset of 143 children who underwent multiple measurements. No differences in height were apparent between NF1 and normal subjects up to age 7 (girls) and 12 (boys) years; subsequently, the 50th centile of NF1 subjects tends to overlap with the 25th centile of normal subjects, and the 3rd centile is much lower in NF1 subjects than in normal subjects, mainly during adolescence. The negatively skewed distribution of height seems to indicate that height growth impairment affects only a proportion of NF1 subjects; height growth impairment does not seem related to disease severity. As for weight, our data suggest that slight overweight is a characteristic of adult NF1 subjects (mainly among males), independent of disease severity. Height growth velocity is normal during childhood for both sexes, whereas the pubertal spurt is slightly anticipated and reduced in NF1 boys but not in girls. Our data confirm previous observations that macrocrania affects most NF1 subjects; the shape of the head growth curve is similar in NF1 and normal girls, whereas NF1 boys present an OFC pubertal growth spurt much more pronounced and delayed than normal boys. The disproportion between OFC and height seems to be related to disease severity in boys but not in girls. Growth charts presented here can be useful in neurofibromatosis clinics for the identification of the effects of secondary growth disorders, for growth prognosis, and for the evaluation of the effects of a therapy such as GH therapy after radiotherapy for optic glioma.

Adolescent↗

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.

Aortic Coarctation↗

The relationship between nephroblastoma and neurofibromatosis (Von Recklinghausen's disease).

Three cases with co-existent Wilm's tumor and Von Recklinghausen's Disease from a series of 342 nephroblastomas are discussed as to the significance of this association. Biological arguments favor a positive link because of the multiplicity of associative lesions which parallel each other, the co-existence of which suggests a common genetic bond. An embryologic association is described whereby early mutational events, i.e. neural induction of nephrogenesis, may link these two entities in utero. Further interconnection is stated statistically, in that nephroblastoma patients in this series had a 29 fold higher incidence of multiple neurofibromatosis than predicted for in the general population. The co-existent diseases in the three cases observed are approximately 33-50% more than can be accounted for by chance in the United States population. Malignant transformation in neurofibromatosis is discussed because of the therapeutic implications presented by two of the three Wilms' tumor patients studied.

Child, Preschool↗

Angiosarcoma developing in a patient with Neurofibromatosis (von Recklinghausen's disease).

The authors present an angiosarcoma of the scrotum and penis. The disease occurred in a 61-year-old man with a long history of neurofibromatosis (von Recklinghausen's disease). The histologic and ultrastructural features are described. The authors speculate that the angiosarcoma, which developed in a location without histologic evidence of neurofibromatosis, possibly represents an expression of an abnormal genome in vascular tissue. The angiosarcoma responded to radiation therapy only temporarily, recurred after surgery, and did not respond to Adriamycin, dactinomycin or cis-platinum. The patient died three years after the onset of his angiosarcoma.

Hemangiosarcoma↗

Evidence of chromosomal instability in neurofibromatosis.

Blood lymphocytes from six unrelated patients with neurofibromatosis and three normal controls were examined for their response to different doses (0, 75, 150, 300, 400 rad) of x-radiation, as measured by chromosome aberrations (gaps, breaks, dicentrics, centric rings, acentric ring, fragments, and minutes). Cytogenetic studies on phytohemagglutinin-stimulated cells revealed chromosomal instability in the neurofibromatosis lymphocytes as shown by the significant increase in the in the incidence of gaps, breaks and dicentrics. This increase paralleled the increase in the dose of irradiation. The significance of these findings is discussed.

Adolescent↗

Enhanced response to the induction of sister chromatid exchange by gamma radiation in neurofibromatosis.

The study included 8 unrelated patients with neurofibromatosis, and 10 unrelated normal and healthy persons as controls. Whole blood samples were divided into plastic T flasks and exposed at room temperature to gamma rays. The radiation dose was 36 rad/minute, and the doses delivered were 0, 75, 150 and 300 rad. The lymphocytes were cultured in (RPMI) 1640 tissue culture medium and autologous serum (20%). Phytohemagglutinin and bromodeoxyuridine (Brdu) (10 microM) were added at initiation of culture and harvesting was done 64 to 68 hours after culture initiation. Slides were coded, differential staining was done, and sister chromatid exchanges (SCEs) and aberrations (gaps, breaks, dicentrics, fragments and minutes) were counted. In the controls no significant increase in frequency of SCE has been found (P greater than 0.5). In the patients, the frequencies significantly increased with the increase of dose of irradiation (P less than 0.001). Furthermore, after irradiation, the incidence of gaps, breaks, and dicentrics were significantly increased in patients compared with controls. Moreover, the incidence increased with the increase in the dose of radiation. The results are discussed with a conclusion that the results add to the indication of a genetic predisposition to develop cancer in neurofibromatosis patients.

Adolescent↗