I'm afraid I can't help, but did you get an answer in the end? I have NF and am very worried about the chances of my children inheriting it.
I am sorry to say that NF is an autosomal dominant disorder, so 1 parent results in > or = 50% chance of the child inheriting the disorder.
There are two types of Neurofibromatosis, (NF): NF 1 and NF 2. NF 1is more prevalent and accounts for ~90% of NF cases. NF 1 is caused by a mutation of neurofibromin 1 (tumor suppressor) on chromosome 17q11.2 causing the loss of inhibitory control on the p21 ras oncoprotein (resulting in unchecked cellular proliferation and tumor growth.)
Neurofibromatosis type II (NF-2) is also known as “central neurofibromatosis” and is caused by a mutation of the “Merlin” gene (tumor suppressor) on chromosome 22q12. The merlin gene product regulates meningioma cell growth, and the mutation of said gene manifests as non-malignant tumors in the auditory-vestibular nerve (vestibulocochlear nerve or cranial nerve VIII) often leading to hearing loss and visual deficits. The reason I make the distinction is because of the differential symptom expression based on different genotypes in NF-1 but not NF-2 (discussed below).
Both of these types of NF are autosomal dominant. Therefore, receiving a single copy of the mutated gene is needed to inherit the disorder.
Because these are autosomal dominant disorders, there is unfortunately a high chance of someone with NF-1 or NF-2 passing the mutation on to their offspring. If one parent has the disorder and the other parent does not, a child will have a 50 – 100% chance of inheriting the disorder. The probability depends on whether the NF parent’s genotype is homozygous (AA) or heterozygous (Aa) for the trait. (Here “A” is the dominant allele and “a” is recessive.)
Genotype refers to the genes which code for the trait, while phenotype refers to the expression of the trait.
In NF-1, there have not been any conclusive links between genotype and phenotype – which may explain the large variable expressivity in the severity and exact symptoms of NF-1. Variable expressivity refers to the occurrence of different individuals sharing the same genotype, but with widely differing phenotypes. For example two people could have the same heterozygous genotype “Aa” for this trait, yet differing symptoms and severity.
In NF-2 however, there is a strong correlation between the genotype and phenotype, and the disorder manifests similarly within family members.
Studies in NF-2 patients have compared the specific type of mutation and the nature of manifestation and progression of the disease in other words to see if a certain mutation produce a specific mixture of symptoms.
The results show that specific mutation types resulted in different prognoses. For example, subjects with Frameshift mutations and Nonsense mutations had a poorer prognosis than subjects with Missense mutations. However, there were cases of identical genotypes resulting in very divergent symptomology, which suggests environmental factors may influence how NF manifests in different individuals.
Prenatal tests such as CVS and Amniocentesis can diagnose NF in vivo.
Good luck. There are numerous clinical trials (see ClinicalTrials.gov) and pioneering treatments (Mayo Clinic).