scoliosis

GM1 Gangliosidosis

Clinical Characteristics
Ocular Features: 

Based on clinical manifestations, three types have been described: type I or infantile form, type II or late-infantile/juvenile form, and type III or adult/chronic form but all are due to mutations in the same gene.  Only the infantile form has the typical cherry red spot in the macula but is present in only about 50% of infants.  The corneal clouding is due to intracellular accumulations of mucopolysaccharides in corneal epithelium and keratan sulfate in keratocytes.  Retinal ganglion cells also have accumulations of gangliosides.  Decreased acuity, nystagmus, strabismus and retinal hemorrhages have been described. 

Systemic Features: 

Infants with type I disease are usually hypotonic from birth but develop spasticity, psychomotor retardation, and hyperreflexia within 6 months.  Early death from cardiopulmonary disease or infection is common.  Hepatomegaly, coarse facial features, brachydactyly, and cardiomyopathy with valvular dysfunction are common.  Dermal melanocytosis has also been described in infants in a pattern some have called Mongolian spots.  Skeletal dysplasia is a feature and often leads to vertebral deformities and scoliosis.  The ears are often large and low-set, the nasal bridge is depressed, the tongue is enlarged and frontal bossing is often striking.  Hirsutism, coarse skin, short digits, and inguinal hernias are common.

The juvenile form, type II, has a later onset with psychomotor deterioration, seizures and skeletal changes apparent between 7 and 36 months and death in childhood.  Visceral involvement and cherry-red spots are usually not present. 

Type III, or adult form, is manifest later in the first decade or even sometime by the 4th decade.  Symptoms and signs are more localized.  Neurological signs are evident as dystonia or speech and gait difficulties.  Dementia, parkinsonian signs, and extrapyramidal disease are late features.  No hepatosplenomegaly, facial dysmorphism, or cherry red spots are present in most individuals. Lifespan may be normal in this type. 

Genetics

This is an autosomal recessive lysosomal storage disease secondary to a mutations in GLB1 (3p21.33).  It is allelic to Morquio B disease (MPS IVB) (253010).  The mutations in the beta-galactosidase-1 gene result in intracellular accumulation of GM1 ganglioside, keratan sulfate, and oligosaccharides.  The production of the enzyme varies among different mutations likely accounting for the clinical heterogeneity. 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no treatment that effectively alters the disease course. 

References
Article Title: 

Neurofibromatosis Type I

Clinical Characteristics
Ocular Features: 

Melanocytic iris hamartomas, sometimes called Lisch nodules, are considered pathognomonic of this disease but are found in only about 75% of patients.  These appear as sharply defined, smooth masses on the stromal surface and consist of spindle cells of melanocytic origin.  Their presence correlates with the severity of skin freckles and cafe-au-lait spots.  Also characteristic of neurofibromatosis 1 are eyelid fibromas causing ptosis and the familiar horizontal S-sign in the upper lid margin but these are only found in one-third of patients.  Ciliary body cysts have been reported to occur at a frequency of 78%, or 10 times more frequently than in unaffected individuals.  Nearly half of patients have occludable anterior chamber angles (Types 1 and 2).

Gliomas of the optic nerves, chiasm or optic tracts are slow growing astrocytomas that occur in about 15% of children at a mean age of about 5 years.  While these comprise the most common intracranial tumors in NF1, they typically have a benign course and may even regress.  However, some present as precocious puberty and severe loss of acuity may occur before discovery.

Vascular lesions of the retina are also sometimes seen and may be responsible for rubeosis and neovascular glaucoma.

Systemic Features: 

Vascular anomalies are often seen and those that impact blood supply to the kidneys can induce severe hypertension especially in children (pheochromocytomas are also a risk).  Coarctations and aneurysmal anomalies can obstruct the blood supply to major organs, sometimes acutely.  Some degree of cognitive impairment and sometimes mental retardation can be seen in nearly half of patients, even in the absence of other obvious neurological deficits.  Short stature, tibial pseudoarthrosis, sphenoid dysplasia, and scoliosis are common.  Osteopenia and frank osteoporosis are seen in approximately half of patients.  A small percentage of patients develop malignant peripheral nerve sheath tumors (lifetime risk 8-13%).  Rare patients develop other malignancies, primarily sarcomas.

Diagnosis is based on the presence of some combination of typical features such as cafe-au-lait spots, Lisch nodules, neurofibromas, optic pathway gliomas, axillary or groin freckling, and bone dysplasia.  The underlying disease is progressive and the accuracy of diagnosis improves in older patients.

Genetics

The typical disease is caused by mutations in the NF1 gene (17q11.2) and inherited as an autosomal dominant disorder.  However, about half of patients have new mutations with males having the higher mutation rate.  Penetrance is nearly 100% among those who have mutations in NF1. There is evidence that the gene product is a tumor suppressor protein (neurofibromin) and the clinical features can also result from deactivation of both copies of the gene via the two hit mechanism of Knudson.  This has been proposed as a mechanism to explain the high degree of variability of clinical disease within families as the expression depends upon which cell lines experience postzygotic somatic mutations.

Watson syndrome (193520) is also the result of NF1 mutations and shares some clinical features such as neurofibromas, Lisch nodules, shortness of stature, cognitive deficits, and cafe-au-lait spots.  It may be an allelic disorder.

Neurofibromatosis type II (101000), with less cognitive problems, results from mutations in NF2.  Lisch nodules are less common in type II but acoustic neuromas are more common than in type I.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no treatment for the underlying disease but lifelong monitoring is necessary because of the widespread manifestations and serious threat of complications such as visual impairment, renal hypertension and ischemia of major organs.

References
Article Title: 

Goldenhar Syndrome Spectrum

Clinical Characteristics
Ocular Features: 

There is considerable clinical heterogeneity in this syndrome.  Upper eyelid colobomas and ocular dermoids or lipdermoids are the primary ocular signs (lower lid colobomas are more common in Treacher Collins-Franceschetti syndrome [154500]).  The caruncles may be dysplastic, displaced or even bilobed.  Iris, optic nerve and chorioretinal colobomas also occur.  Microphthalmia is uncommon.  All ocular features are usually unilateral but are bilateral in a minority of cases.

Systemic Features: 

The facial asymmetry (hemifacial microsomia) can be a striking feature.  The side with microsomia may have a malformed external auricle, preauricular tags, pretragal fistulas, and microtia or even atresia of the external auditory canal.  A wide variety of other anomalies are often found including left lip and palate, mandibular hypoplasia, vertebral anomalies, facial nerve paralysis, congenital heart defects, and conductive hearing loss.  Mental deficits are often present along with features of the autism spectrum in 11%.

Genetics

Most cases are sporadic but other family patterns support autosomal recessive and autosomal dominant inheritance with the latter being the most common.  A locus at 14q32 has been associated with OAVS but so far no mutant gene has been identified.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Some patients benefit from scoliosis and cosmetic surgery.  Assistive hearing devices can be helpful and children especially should be monitored for physical and cognitive development.

References
Article Title: 

Oculo-auriculo-vertebral spectrum: clinical and molecular analysis of 51 patients

Beleza-Meireles A, Hart R, Clayton-Smith J, Oliveira R, Reis CF, Venancio M, Ramos F, Sa J, Ramos L, Cunha E, Pires LM, Carreira IM, Scholey R, Wright R, Urquhart JE, Briggs TA, Kerr B, Kingston H, Metcalfe K, Donnai D, Newman WG, Saraiva JM, Tassabehji M. Oculo-auriculo-vertebral spectrum: clinical and molecular analysis of 51 patients. Eur J Med Genet. 2015 Sep;58(9):455-65.

PubMed ID: 
26206081

Marinesco-Sjogren Syndrome

Clinical Characteristics
Ocular Features: 

Congenital cataracts are one of the cardinal features of Marinesco-Sjogren syndrome but lens opacities may have a later onset and may be progressive as well.  Strabismus and nystagmus are sometimes present.

Systemic Features: 

Non-ocular features include cerebellar atrophy, psychomotor developmental delays, mental retardation, and muscle weakness.  Dysarthria is common.  The myopathy has its onset in childhood and is progressive with weakness, hypotonia, and atrophy eventually leading to total disability in some cases.  Progression of motor dysfunction may, however, stabilize in some patients but at an unpredictable level.  Infants are often 'floppy babies'.  MRI studies reveal cerebellar atrophy.  Serum creatine kinase levels are increased and muscle biopsies show chronic myopathic changes.  Skeletal features include short stature, pectus carinatum, and secondary kyphoscoliosis and foot deformities.  Bone abnormalities may be seen in the digits.

Genetics

This is an autosomal recessive condition resulting from mutations in the SIL1 gene (5q31).  It is sometimes confused with the condition known as congenital cataracts, facial dysmorphism, and neuropathy (604168) with which it shares some clinical features.  The two conditions are genetically distinct since they are caused by mutations in different genes.

See also Muscular Dystrophy, Congenital Cataracts, with Cataracts and Intellectual Disability for a similar disorder caused by a different mutation.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Visually significant cataracts may need to be removed in the first decade of life.  Skeletal deformities may benefit from surgery and hormone therapy should be considered in specific cases.

References
Article Title: 

The gene disrupted in Marinesco-Sjögren syndrome encodes SIL1, an HSPA5 cochaperone

Anttonen AK, Mahjneh I, Hamalainen RH, Lagier-Tourenne C, Kopra O, Waris L, Anttonen M, Joensuu T, Kalimo H, Paetau A, Tranebjaerg L, Chaigne D, Koenig M, Eeg-Olofsson O, Udd B, Somer M, Somer H, Lehesjoki AE. The gene disrupted in Marinesco-Sjogren syndrome encodes SIL1, an HSPA5 cochaperone. Nat Genet. 2005 Dec;37(12):1309-11.

PubMed ID: 
16282978

Linkage to 18qter differentiates two clinically overlapping syndromes: congenital cataracts-facial dysmorphism-neuropathy (CCFDN) syndrome and Marinesco-Sjogren syndrome

Lagier-Tourenne C, Chaigne D, Gong J, Flori J, Mohr M, Ruh D, Christmann D, Flament J, Mandel JL, Koenig M, Dollfus H. Linkage to 18qter differentiates two clinically overlapping syndromes: congenital cataracts-facial dysmorphism-neuropathy (CCFDN) syndrome and Marinesco-Sjogren syndrome. J Med Genet. 2002 Nov;39(11):838-43.

PubMed ID: 
12414825

Ehlers-Danlos Syndrome, Type VIA

Clinical Characteristics
Ocular Features: 

The globe is thin and fragile and ruptures easily.  This results from scleral fragility which is in contrast to type VIB EDS  (229200) in which the cornea seems to be more fragile.  Retinal detachment is always a risk but no quantitative assessment can be made since early case reports did not always provide good classification of EDS types.  Other ocular abnormalities such as keratoconus and structural changes in the cornea are less common but frequent changes in classification and lack of genotyping in early cases make definitive clinical correlations difficult.

Systemic Features: 

The primary clinical manifestations of this form (VIA) of Ehlers-Danlos syndrome are extraocular.   The skin is soft, thin, easily extensible, and bruises easily.  The joints are highly flexible with a tendency to dislocate.  Arterial ruptures are not uncommon, often with severe consequences.  Scoliosis begins almost at birth and often progresses to severe kyphoscoliosis.  Patients are floppy (hypotonic).  Intellect is normal and there are generally no developmental delays.  Thirty per cent of infants have a club foot at birth.

Genetics

This an autosomal recessive disorder caused by molecular defects in the PLOD1 gene (1p36.3-p36.2).  The gene product is an enzyme, lysyl hydroxylase 1, important for the normal crosslinking of collagen. Mutations in PLOD1 may result in hydroxylase dysfunction with abnormal hydroxylation of lysine, weakened crosslinks, and fragile tissue.  

The classification of Ehlers-Danlos disease is under constant revision as new mutations and clinical subtypes are found (see 130000).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Joint dislocations, ocular trauma and vascular ruptures require prompt attention.  Longevity is not impacted by this syndrome.

References
Article Title: 

Marfan Syndrome

Clinical Characteristics
Ocular Features: 

Marfan syndrome typically has skeletal, ocular and cardiovascular abnormalities.  The globe is elongated creating an axial myopia and increasing the risk of rhegmatogenous retinal detachments.  Ectopia lentis is, of course, the classical ocular feature and is often if not always congenital with some progression.  The lenses most frequently dislocate superiorly and temporally and dilating the pupils often reveals broken and retracted lens zonules.  Phacodenesis and iridodenesis are commonly present even in the absence of evident lens dislocations. Cataracts develop several decades earlier than in unaffected individuals. The cornea is generally several diopters flatter than normal and there is an increased risk of open angle glaucoma.  There is considerable clinical variation among patients.

Systemic Features: 

Patients with the Marfan phenotype are usually tall with disproportionately long limbs (dolichostenomelia) and digits (arachnodactyly).   Patients frequently have scoliosis or kyphoscoliosis.  The joints are lax and hyperflexible although contractures can also occur.  The sternum is often deformed, either as a pectus excavatum, or sometimes pectus carinatum.  The hard palate is high and narrow resulting in crowding of the teeth and maloccclusion.  The defect in fibrillin is responsible for the weakness in connective tissue that leads to frequent cardiac valve malfunction, especially insufficiency of the aortic valve resulting from aortic dilatation, tear, and rupture.  The latter is often life-threatening as aortic dissection can be fatal.  Mitral valve prolapse is seen as well.  Cardiovascular disease is primarily responsible for the shortened life expectancy in this disease, more pronounced among males.

Genetics

As many as 25% of cases are caused by new mutations, but familial cases usually follow an autosomal dominant pattern of inheritance.  Autosomal recessive inheritance is claimed for several individuals in a consanguineous Turkish family.  Mutations in the fibrillin-1 gene (FBN1) on chromosome 15 (15q21.1) are considered responsible for the typical phenotype.  The exact nature of the fibrillin defect is unknown but the result is a generalized weakness in connective tissue.

The same gene is mutant in the autosomal dominant form of the Weill-Marchesani syndrome (608328) which is allelic to the Marfan syndrome.

Mutations in FBN1 have also been found in cases with isolated autosomal dominant ectopia lentis (129600).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Isometric exercises such as weight lifting should be avoided as should contact sports in which blunt trauma to the chest may occur because of the weakened aortic wall due to cystic changes that predispose the athlete to aortic dissection.  A dislocated and/or cataractous lens may need to be removed from the visual axis, and, of course, periodic retinal examinations for retinal holes and retinal detachments should be made.   Beta-adrenergic blockade reduces the risk of aortic dilatation and improves survival.

Pravastatin has been reported to reduce aortic dilation in marfan mice.

References
Article Title: 

Pravastatin reduces marfan aortic dilation

McLoughlin D, McGuinness J, Byrne J, Terzo E, Huuskonen V, McAllister H, Black A, Kearney S, Kay E, Hill AD, Dietz HC, Redmond JM. Pravastatin reduces marfan aortic dilation. Circulation. 2011 Sep 13;124(11 Suppl):S168-73.

PubMed ID: 
21911808

McCune-Albright Syndrome

Clinical Characteristics
Ocular Features: 

This disorder is of interest to ophthalmologists because compression of the optic nerve can occur from fibrous dysplasia of the canal.  However, this occurs only in some cases.  The risk of optic neuropathy is higher in patients with elevated levels of growth hormone.

Systemic Features: 

This disorder is clinically heterogeneous because of the variable degree of involvement of all bony tissue.  The primary manifestations are secondary to endocrine dysfunction and fibrous dysplasia.  Thyrotoxicosis, Cushing syndrome, pituitary gigantism, hearing deficits, and precocious puberty (in both sexes) are common.  The skin often has a cafe-au-lait pattern of pigmentation.

Genetics

Postzygotic activating mutations in the GNAS gene on chromosome 20 (20q13.2) are likely responsible for this disorder although too few familial cases have been reported to document a mode of inheritance.  It has been suggested that an autosomal dominant lethal gene is involved with survival only in the presence of significant mosaicism.

Treatment
Treatment Options: 

Recent evidence suggests that early treatment (before age 18 years) in patients with elevated growth hormone levels using pharmacologic intervention, surgery, and/or radiotherapy is associated with less optic neuropathy compared with patients who are treated later.  The impact on hearing impairment is less certain and awaits further studies.

Not all patients have significant optic nerve compression. Decompression of the optic nerve canal is beneficial in about half of cases in which significant nerve encasement is present but should be performed only when progressive optic neuropathy occurs, especially when growth hormone levels are elevated.

References
Article Title: 

McCune-Albright syndrome

Dumitrescu CE, Collins MT. McCune-Albright syndrome. Orphanet J Rare Dis. 2008 May 19;3:12.

PubMed ID: 
18489744

Basal Cell Nevus Syndrome

Clinical Characteristics
Ocular Features: 

Eyelid basal-cell carcinomas are the most common ocular finding of this syndrome.  These malignancies may be multiple and may occur on the neck, chest, back, arms and elsewhere on the face.   Those on the eyelids generally have their onset in the postpubertal period, usually by age 35 years, and are often multiple.  Their indolent nature can result in considerably delay in diagnosis, however, and local recurrences are common.  Deformities of the skull often result in the appearance of hypertelorism and proptosis.  Epidermal cysts are found in one-fourth of patients, especially on the palms, but may occur in the tarsal conjunctiva as well.  Intratarsal keratinous eyelid cysts occur in 40% of patients.  Less common reported ocular findings are colobomas, glaucoma, nystagmus, strabismus, and cataracts but these may simply be associations.

Systemic Features: 

This disorder is one of a few in which a disposition to neoplasia is associated with skeletal deformities.  These include bifid ribs, scoliosis, skull deformities such as frontal bossing, increased occipitofrontal circumference, broad nasal root with hypertelorism, mandibular prognathia, and bony cysts.  Medulloblastoma is an infrequent but important sign.  Palmar and/or plantar pits are often present.  Basal cell carcinomas and jaw cysts occur in over 90% of patients by the age of 40 years.  Invasive oral tumors are found in 78% of individuals.

Genetics

This is an autosomal dominant disorder, caused by heterozygous mutations in the PTCH1 gene located on chromosome 9 (9q22.3).  Interestingly, somatic mutations in the PTCH1 gene have also been found in isolated cases with only basal cell carcinoma or medulloblastoma.  Perhaps 40% of cases arise de novo, i.e., without a family history, and older paternal age at conception increases the risk of new mutations.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Treatment is directed at the location of clinical disease with excision of basal cell carcinomas having the highest priority.  Patients must be monitored throughout life for new lesions as well as recurrence at treated sites. Radiotherapy and non-essential diagnostic X-rays should probably be avoided due to sensitivity to ionizing radiation.

Oral administration of an experimental small molecule signaling inhibitor (GDC-0449 or Vismodegib; Genetech) of the Hedgehog signaling pathway has shown promise in reduction of the number of new lesions as well as shrinkage of existing skin lesions.  BCC lesions have been successfully treated with ingenol mebutate in a single patient.

References
Article Title: 

Eyelid Cysts in Gorlin Syndrome: A Review and Reappraisal

Wolkow N, Jakobiec FA, Yoon MK. Intratarsal Keratinous Eyelid Cysts in Gorlin Syndrome: A Review and Reappraisal. Surv Ophthalmol. 2017 Dec 26. pii: S0039-6257(17)30236-9. doi: 10.1016/j.survophthal.2017.12.007.

PubMed ID: 
29287708

Basal cell nevus syndrome: a brave new world

Goldberg LH, Firoz BF, Weiss GJ, Blaydorn L, Jameson G, Von Hoff DD. Basal cell nevus syndrome: a brave new world. Arch Dermatol. 2010 Jan;146(1):17-9. PubMed PMID: 20083687.

PubMed ID: 
20083687

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