Approximately 25% of patients will require corrective surgery.Skeletal muscle weakness and motor control deficits
Deficits in motor function in NF-1 have been long recognised and have been historically attributed to nerve dysfunction. In recent years however, studies suggest NF-1 is associated with a primary problem in muscle function (myopathy).Clinical findings in people with NF-1 include:

Reduced skeletal muscle size
Reduced exercise capacity
Muscle weakness (The most recent study reports between 30–50% reduced upper and lower limb muscle strength in NF-1 children compare with matched controls).Studies in genetically modified mice have thus far confirmed that the NF1 gene is vital for normal muscle development and metabolism. Knockout of the NF1 gene in muscle results in deregulated lipid metabolism and muscle weakness.NF-1 is a disease in the RASopathy family of diseases, which include Costello Syndrome, Noonan Syndrome, and Cardiofaciocutaneous syndrome. The RASopathies also present with skeletal muscle weakness. It is likely that impaired muscle function in these disorders is linked to altered Ras/MAPK signalling, however, the precise molecular mechanisms remain unknown. Facial bones and limbs
Bowing of a long bone with a tendency to fracture and not heal, yielding a pseudarthrosis. The most common bone to be affected is the tibia, causing congenital pseudarthrosis of the tibia or CPT. CPT occurs in 2–4% of individuals with NF-1. Treatment includes limb amputation or correction by Ilizarov method as a limb-sparing technique. Malformation of the facial bones or of the eye sockets (lambdoid suture defects, sphenoid dysplasia)
Unilateral overgrowth of a limb.
Osteosclerosis is a disorder that is characterized by abnormal hardening of bone and an elevation in bone density. It may predominantly affect the medullary portion and/or cortex of bone. Plain radiographs are a valuable tool for detecting and classifying osteosclerotic disorders. It can manifest in localized or generalized osteosclerosis. Localized osteosclerosis can be caused by Legg–Calvé–Perthes disease, sickle-cell disease and osteoarthritis among others. Osteosclerosis can be classified in accordance with the causative factor into acquired and hereditary. Types
Acquired osteosclerosis
Osteogenic bone metastasis caused by carcinoma of prostate and breast
Pagets disease of bone
Myelofibrosis (primary disorder or secondary to intoxication or malignancy)
Osteosclerosing types of chronic osteomyelitis
Hypervitaminosis D
hyperparathyroidism
Schnitzler syndrome
MastocytosisSkeletal fluorosis

Monoclonal IgM Kappa cryoglobulinemia
Hepatitis C.

Hereditary osteosclerosis
Malignant infantile osteopetrosis
Neuropathic infantile osteopetrosis
Infantile osteopetrosis with renal tubular acidosis
Infantile osteopetrosis with immunodeficiency
IO with leukocyte adhesion deficiency syndrome (LAD-III)
Intermediate osteopetrosis
Autosomal dominant osteopetrosis (Albers-Schonberg)
Pyknodysostosis (osteopetrosis acro-osteolytica)
Osteopoikilosis (Buschke–Ollendorff syndrome)
Osteopathia striata with cranial sclerosis
Mixed sclerosing bone dysplasia
Progressive diaphyseal dysplasia (Camurati–Engelmann disease)
SOST-related sclerosing bone dysplasias

Diagnosis
Osteosclerosis can be detected with a simple radiography. There are white portions of the bone which appear due to the increased number of bone trabeculae. Animals
In the animal kingdom, there also exists a non-pathological form of osteosclerosis, resulting in unusually solid bone structure with little to no marrow. It is often seen in aquatic vertebrates, especially those living in shallow waters, providing ballast as an adaptation for an aquatic lifestyle. It makes bones heavier, but also more fragile. In those animal groups, osteosclerosis often occurs together with bone thickening (pachyostosis). This joint occurrence is called pachyosteosclerosis. See also
Pachyostosis
Pachyosteosclerosis
Heinrich Albers-Schönberg

References


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