Familial Neurofibromatosis Type Research Articles

Giant café-au-lait macule in neurofibromatosis 1: A type 2 segmental manifestation of neurofibromatosis 1?

Type 2 segmental manifestation of autosomal dominant dermatoses refers to pronounced segmental lesions superimposed on the ordinary nonsegmental phenotype, indicating loss of heterozygosity occurring at an early stage of embryogenesis. We describe a 20-year-old Taiwanese woman with typical lesions of neurofibromatosis type 1 (NF1) in the form of characteristic café-au-lait spots, neurofibromas, axillary freckling and Lisch nodules. In addition, a giant garment-like or "bathing-trunk" café-au-lait macule involved the lower half of the trunk, the buttocks, and parts of the thighs, being superimposed on the ordinary smaller spots of NF1. This large café-au-lait macule may be best explained as an example of type 2 segmental NF1. A novel mutation (3009delG) in exon 23 was also identified in this patient, which has not yet been described in sporadic and familial NF1.

Unidentified bright objects on brain MRI in children as a diagnostic criterion for neurofibromatosis type 1

Lesions of the brain denominated as unidentified bright objects (UBOs), which are not included in the diagnostic criteria for neurofibromatosis type 1 (NF1) established by the National Institutes of Health (NIH), have been detected by MRI. The purpose of this study was to investigate the possibility of including the presence of UBOs as a diagnostic criterion for NF1 in children. The study included 88 children between the ages of 2 and 18 years. The case group consisted of 40 children diagnosed with sporadic or familial NF1 according to the criteria established by the NIH. A control group consisted of 48 individuals referred for routine MRI of the brain for other complaints not related to NF1. UBOs were identified in 70% of the NF1 patients and in none of the control group. The sensitivity of the presence of UBOs for the diagnosis of NF1 was 70% (CI 53-83%), with a false-negative rate of 30% (CI 27-47%), a specificity of 100% (CI 86-100%) and a false-positive rate of 0% (CI 0-14%). Faced with the difficulties in diagnosing NF1 in children and the high frequency and specificity of the presence UBOs identified by MRI in our series, we recommend the inclusion of the presence UBOs as a diagnostic criterion for NF1 in children.

Parental Reports of Health-Related Quality Of Life in Young Children with Neurofibromatosis Type 1: Influence of Condition Specific Determinants

To assess the health-related quality of life of 34 Dutch children 12 to 72 months of age with neurofibromatosis type 1 (NF1) using the Infant/Toddler Quality of Life Questionnaire (ITQOL) and to investigate the potential impact of clinical factors on parental reports of health-related quality of life. A parent-completed form including the ITQOL, NF1-specific questions, and sociodemographic questions was sent. ITQOL scale scores were compared for the study population against Dutch reference values. The influence of general and clinical characteristics on ITQOL scale scores was evaluated with multivariate analysis. A significant impact was observed on most aspects of quality of life, particularly for growth and development, general health perceptions and parental impact. The lowest scores were observed in children with complications because of NF1. ITQOL scale scores were affected by parental educational level, familial NF1, and parental reports of complications of NF1 and perceived disease severity. Important aspects of health-related quality of life were observed to be negatively affected in children with NF1, as measured by the ITQOL. Family-related and disease-related variables appeared to influence the quality of life in children with NF1.

Meningioangiomatosis. Descripción de dos casos y revisión de la literatura

Meningioangiomatosis (MA) is a rare benign intracraneal lesion. The majority of cases are sporadic although the association of this lesion with familial neurofibromatosis (NF) type 2 is well known. NF-associated MA may be multifocal and is often asymptomatic and diagnosed at autopsy. Non-associated cases are usually symptomatic, occurs in children and young adults and frequently arise in leptomeninges and underlying cerebral cortex. In the present work, we describe two new non-associated cases of MA in two boys, seven and one year old with seizures that disappeared after surgical excision. Histopathologically, the lesion was predominantly cellular in one case and more fibrous in the other. From the literature review we concluded that sporadic cases present as single lesions which manifest by seizures or persistent headaches. Rarely MA has been described to coexist with meningiomas. Histopathologically, MA is characterized by a plaque-like proliferation of meningothelial and fibroblast- like cells surrounding small vessels and trapping islands of gliotic cortical tissue. The lesion does not show significant atypia, mitosis or necrosis. Although all cases of MA share unifying features, there are different degrees of histological presentation with cases predominantly cellular and others more fibrous and calcified. This could correspond to different stages in the evolution of the MA. Symptoms disappear with the complete excision of the lesion.

Puberty and growth in children and adolescents with neuro fibromatosis type 1

This study evaluates anthropometric and pubertal development parameters in children and adolescents with sporadic and familial occurrence of neurofibromatosis type 1 (NF-1). The study involved 23 patients (15 boys, 8 girls) with sporadic (n=12) and familial NF-1(7 affected mothers and 4 fathers), with average age of 12 years (range 5-20 years). All patients answered to a standard questionnaire including family and personal data and, following, they underwent systematized physical examination, with special attention to anthropometric data, dermatologic and pubertal stage according to Tanner's criteria evaluation. Short stature was detected in a 17 year-old patient, 148.5cm height, with score Z of -4.16 and being the even outside of the family conduit. Three male patients had head circumference above of + 2DP from on average for the age. It was not found no case of precocious or delayed puberty. In our study, do not we find significant alterations regarding the stature and pubertal development.

Association neurofibromatose de type I et sclérose en plaques

Association between neurofibromatosis type 1 (NF-1) and multiple sclerosis (MS) has been very rarely described. We report the case of a 40-year-old woman presenting familial NF-1 who had café au lait spots and cutaneous neurofibromatosis since childhood. Five years earlier, she experienced a first episode of unilateral optic neuritis, recurrent sensory and motor disturbances, then gait ataxia and pyramidal tract dysfunction with progressive walking impairment. Altered evoked potentials, CSF analysis and cerebral MRI findings were consistent with the diagnosis of MS (secondary progressive form after relapsing-remitting phase). We review major demographic, clinical and laboratory data of MS associated with NF-1 and discuss about the potential pathophisiological mechanisms implied.

Unusual form of recurrent giant cell granuloma of the mandible and lower extremities in a patient with neurofibromatosis type 1

We report on a girl with familial neurofibromatosis type 1 (Nf1) who at age 11 had multiple osteolytic lesions of the right mandible and the distal femoral and proximal tibial metaphyses bilaterally. No other skeletal component was affected, and no abnormalities were present on skeletal radiographs of her parents. Histologic examination of the mandibular and right femoral lesions revealed a “multinucleated giant cell process.” Results of repeated routine laboratory and bone metabolic studies were within normal limits. The lack of reliable histologic criteria and the diagnostic problems in distinguishing among central giant cell granulomata, giant cell tumors of the jaw, cherubism, brown tumors resulting from (occult) hyperparathyroidism, Jaffé-Campanacci syndrome, McCune-Albright syndrome, Noonan-like/multiple giant cell lesion syndrome, and multiple nonossifying fibromas of bone are discussed. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:67-72)

Neurofibromatosis type 1 in childhood: evaluation of clinical and epidemiologic features as predictive factors for severity.

The authors evaluated clinical and epidemiologic features of neurofibromatosis type 1 (NF-1) as predictive factors of severity of the disease. The data were retrieved from medical records of 110 children with NF-1 followed up during the period 1974-1991 (mean duration of follow-up 6.7 years). Presence of macrocephaly correlated with higher grade of severity of the disease (P = 0.018). Familial NF-1 was more common in patients with grade 4 disease than in children with grade 1 severity (P < 0.05; odds ratio 2.9, confidence limits 0.85-10.5). The specificity of positive family history and macrocephaly as predictive factors for the grade 4 disease was 90% and 89%, respectively, and sensitivity was 71% and 36%, correspondingly. Positive predictive value of familial NF-1 and macrocephaly was 24% and 31%, respectively. In conclusion, although patients with family history of NF-1 and with macrocephaly tend to have more severe disease, the clinical utility of these features as predictive factors for severity is limited.

Familial neurofibromatosis type 1 associated with an overgrowth syndrome resembling Weaver syndrome.

The simultaneous occurrence of familial neurofibromatosis type 1 (NF1) and an overgrowth syndrome resembling Weaver syndrome was observed in two related cases (a mother and her son). NF1 was confirmed...

Genetic variation in the 3' untranslated region of the neurofibromatosis 1 gene: application to unequal allelic expression.

Neurofibromatosis type 1 (NF1) is a common genetic disorder caused by inactivation of neurofibromin, a protein capable of modulating signal transduction by activating Ras-GTPase activity. We have used cDNA cloning and Northern blot analysis to confirm the NF1 gene produces alternatively polyadenylated mRNAs with 3' untranslated regions (3' UTR) that show striking evolutionary conservation. Scanning of the 3'UTRs for genetic variation revealed three common sequence polymorphisms (> 30% heterozygosity), one less informative polymorphism (approximately 5% heterozygosity) and one rare variant (1/144 chromosomes). These differences were used to examine relative levels of expression of normal and mutant NF1 alleles in lymphoblast cell lines and in one case, autopsy tissue, from patients with NF1. Unequal allelic expression (up to 4-fold) was observed in a subset of both sporadic and familial NF1 cases. Where linkage phase could be determined, the allele segregating with the disorder displayed a relative reduction in expression. However, the magnitude of this effect was variable suggesting the operation of additional, non-genetic factors in determining the degree of relative expression of the mutant allele.

Homozygous inactivation of the NF1 gene in bone marrow cells from children with neurofibromatosis type 1 and malignant myeloid disorders.

The risk of malignant myeloid disorders in young children with neurofibromatosis type 1 is 200 to 500 times the normal risk. The gene for neurofibromatosis type 1 (NF1) encodes neurofibromin, a protein that negatively regulates signals transduced by Ras proteins. Genetic and biochemical data support the hypothesis that NF1 functions as a tumor-suppressor gene in immature myeloid cells, but inactivation of both NF1 alleles has not been demonstrated in leukemic cells from patients with neurofibromatosis type 1. Using an in vitro transcription and translation system, we screened bone marrow samples from 18 children with neurofibromatosis type 1 and myeloid disorders for NF1 mutations that cause a truncated protein. Mutations were confirmed by direct sequencing of genomic DNA from the patients, and from their affected parents, in cases of familial neurofibromatosis type 1. Specimens from 9 of the 18 children contained abnormal peptide fragments, and truncating mutations of the NF1 gene were found in specimens from 8 of these children. The normal NF1 allele was absent in bone marrow samples from five of the eight children. We detected the same mutation in DNA from the affected parent of each child with familial neurofibromatosis type 1. Both alleles of the NF1 gene are inactivated in leukemic cells in some patients with neurofibromatosis type 1. NF1 appears to function as a tumor-suppressor gene in immature myeloid cells.

Juvenile Xanthogranuloma, Neurofibromatosis, and Juvenile Chronic Myelogenous Leukemia

I read with great interest editorial comments by Riccardi1on possible research implications of article recently published by my colleagues and myself.2However, I was confused by notion of the lack of an excess of inherited cases among patients with triad of NF-1, JXG, and JCML. Our study showed a significant excess of familial neurofibromatosis type 1 (NF-1) among patients with triad compared with patients with NF-1 and juvenile xanthogranuloma (JXG) but without juvenile chronic myelogenous leukemia (JCML) (85% vs 47%,P

Repression of the NF1 gene by Tax may expain the development of neurofibromas in human T-lymphotropic virus type 1 transgenic mice

In familial neurofibromatosis type 1 (NF1), individuals with a germ line-transmitted NF1 mutation develop multiple neurofibromas. To explain the observation that transgenic mice expressing the human T-lymphotropic virus type 1 (HTLV-1) tax gene under the control of the viral regulatory element also develop multiple neurofibromas, we demonstrate that the Tax trans-regulator can functionally repress NF1 gene expression through a cis-acting element located immediately upstream of its transcriptional start site, thereby allowing the development of benign neurofibromas without the need for direct mutations in NF1. We propose that such a mechanism would suffice to epigenetically alter NF1 gene expression. The fact that transgenic animals have localized rather than diffuse neurofibroma formation, however, suggests that additional genetic or epigenetic events may be required for neurofibroma formation.

Nonsense mutations at Arg-1947 in two cases of familial neurofibromatosis type 1 in Japanese.

We report two familial cases of NF1 presenting as C to T transitions changing an Arg-1947 codon to a stop codon. In one of the two families, cosegregation of the mutation with NF1 was demonstrated, indicating this mutation causes the disease in this family. As the same mutation at Arg-1947 has been reported previously in three cases of unrelated Caucasians (two are sporadic; the origin of the other is not reported), the codon at Arg-1947 (CGA) in the NF1 gene is considered to be a hotspot common among different ethnic groups and also among familial and sporadic cases.

Familial neurofibromatosis type 1: Clinical experience with DNA testing

To determine how DNA testing for familial neurofibromatosis type 1 (NF-1) would be used in a clinical setting by patients and physicians, we performed confirmatory DNA testing on 24 individuals with a family history of NF-1 and on nine couples who requested DNA testing for current or future prenatal diagnosis. A further eight families were unsuitable for DNA linkage testing because of their pedigree structure. For the majority of persons the certainty of the test result was 95% to 99%. In five individuals, only one of whom was less than 6 years of age, the DNA-based diagnosis was discrepant with the clinical diagnosis at the time of referral. In all five cases, results of subsequent clinical re-examinations were consistent with the DNA diagnosis. We conclude that DNA testing by linkage analysis may be most useful as an adjunct to the clinical diagnosis of familial NF-1 (1) in children less than 6 years of age in whom the full manifestations may not yet be apparent, (2) in NF-1 families interested in prenatal testing, and (3) when the resources available for a complete clinical examination are limited.

Monosomy 7 Syndrome in an Infant with Neurofibromatosis

A 9-month-old boy with known familial neurofibromatosis type I (NF-1) presented with a clinical and laboratory picture suggestive of juvenile chronic myelomonocytic leukemia (JCMMoL). Chromosomal studies obtained from the bone marrow indicated, however, that he had monosomy 7 syndrome. We believe this is the first reported case of monosomy 7 syndrome in a child with NF in the United States, and that this case complements a recent report of two cases of NF, JCMMoL, and monosomy 7 in Japanese children. Since monosomy 7 syndrome is very difficult to differentiate from JCMMoL or acute nonlymphocytic leukemia (ANLL) unless appropriate chromosomal studies are obtained, we believe it is possible that monosomy 7 may occur with increased frequency in patients with NF-1. Monosomy 7 syndrome might therefore be a significant cause of the known association between NF-1 and nonlymphoid leukemia.