psychomotor retardation

Cataracts, Congenital, and Hypomyelinating Leukodystrophy

Clinical Characteristics
Ocular Features: 

Bilateral cataracts may be present at birth or later in the first decade of life.  The ERG and flash VEPs are normal.

Systemic Features: 

Psychomotor development is initially normal but signs of delay are usually present during the first year of life.  Patients may be able to walk but only with support.  Pyramidal and cerebellar dysfunction, muscle weakness and wasting, dysarthria, truncal hypotonia, intention tremor, and spasticity are evident during the first decade.  Some have seizures.  Cognitive impairment ranges from mild to moderate.  Most patients become wheelchair-bound late in the first decade of life and some do not survive beyond childhood.

Hypomyelination and mild axonal loss may be seen in peripheral nerve biopsies while neuroimaging shows evidence of diffuse and progressive cerebral white matter atrophy.

Genetics

This is an autosomal recessive disorder caused by homozygous mutations in FAM126A (7p15.3) leading to a deficiency of the neuronal protein hyccin.  The result is deficient myelination in both central and peripheral nervous systems.  No symptoms are evident in heterozygotes.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

The cataracts may be surgically removed.  There is no known treatment for the progressive neurologic deterioration but physical therapy and special education may be helpful.

References
Article Title: 

Novel FAM126A mutations in Hypomyelination and Congenital Cataract disease

Traverso M, Assereto S, Gazzerro E, Savasta S, Abdalla EM, Rossi A, Baldassari S, Fruscione F, Ruffinazzi G, Fassad MR, El Beheiry A, Minetti C, Zara F, Biancheri R. Novel FAM126A mutations in Hypomyelination and Congenital Cataract disease. Biochem Biophys Res Commun. 2013 Aug 30. [Epub ahead of print] PubMed PMID: 23998934.

PubMed ID: 
23998934

Phenotypic characterization of hypomyelination and congenital cataract

Biancheri R, Zara F, Bruno C, Rossi A, Bordo L, Gazzerro E, Sotgia F, Pedemonte M, Scapolan S, Bado M, Uziel G, Bugiani M, Lamba LD, Costa V, Schenone A, Rozemuller AJ, Tortori-Donati P, Lisanti MP, van der Knaap MS, Minetti C. Phenotypic characterization of hypomyelination and congenital cataract. Ann Neurol. 2007 Aug;62(2):121-7.

PubMed ID: 
17683097

KID Syndrome

Clinical Characteristics
Ocular Features: 

Superficial punctate keratopathy leads to recurrent corneal erosions and eventually scarring and neovascularization.  Progressive opacification requiring PK often occurs.  These individuals may also suffer loss of eyebrows and eyelashes with trichiasis and thickening of the lid margins.  Corneal erosions and keratoconjunctivitis sicca cause incapacitating symptoms.

Systemic Features: 

The skin may be diffusely erythematous and scaly.  This often becomes patchier with well-demarcated areas especially in skin folds of the neck, axillae, and groin.  Older patients with likely autosomal recessive disease have hepatomegaly and may suffer cirrhosis and liver failure.  Short stature and mental retardation have also been noted.  The hearing loss is neurosensory in type.  Epidermal glycogen deposition has been found in one patient with the presumed recessive disorder.

In the presumed autosomal dominant disease, growth failure, mental retardation and liver disease do not seem to be present.  However, oral and skin squamous cell carcinomas, as well as malignant pilar tumors of the scalp may lead to early death.

Genetics

It is uncertain if one or more entities are represented by the KID syndrome.  Many cases are sporadic but others seem to be transmitted in autosomal recessive or autosomal dominant patterns.  The locus of the mutation is unknown in the recessive form.  In the dominant form, a mutation has been found in the connexin-26 gene, GJB2, gene located at 13q12.11.

See Hereditary Mucoepithelial Dysplasia (158310) for a somewhat similar but unique genodermatosis.  Another is IFAP (308205) but cataracts and hearing loss are not features.

Pedigree: 
Autosomal dominant
Autosomal recessive
Treatment
Treatment Options: 

The use of ocular lubricating preparation may supply significant relief from symptoms but scarring may eventually necessitate penetrating keratoplasty.  The threat of skin cancers and fatal hepatic failure requires monitoring throughout life.

References
Article Title: 

Microphthalmia, Syndromic 1

Clinical Characteristics
Ocular Features: 

Microphthalmia is often a part of other ocular and systemic anomalies.  The full range of essential features of Lenz microphthalmia remains unknown but is often diagnosed in males when colobomas and microcornea are associated with mental deficits together with urogenital and skeletal anomalies.  Microphthalmos may be unilateral and ocular cysts are common.  The globes may be sufficiently small that anophthalmia is sometimes diagnosed but this is a misnomer as some ocular tissue is always present.   Sixty per cent of eyes have colobomas which are often bilateral and may involve the optic disc, choroid, ciliary body, and iris.  Blindness is common.  

Systemic Features: 

A large number of associated systemic anomalies have been reported with this type of microphthalmia.  Skeletal features include microcephaly, spinal deformities, high arched palate, pectus excavatum, absent or dysplastic clavicles (accounting for the narrow or sagging shoulders), and digital anomalies including syndactyly, duplicated thumbs and clinodactyly.  Physical growth retardation is evident by shortness of stature.   Urogenital malformations are present in 77% of individuals and include hypospadius, cryptorchidism, hydroureter, and renal dysgenesis.  Dental anomalies include oligodontia and irregular lower incisors that may be widely spaced.  Some degree of intellectual disability is present in 63%.  The ears may be abnormally shaped, low-set, rotated posteriorly, and anteverted. 

Genetics

This is a rare X-linked disorder that is apparently due to an unknown mutation at Xq27-Xq28.  No male-to-male transmission has been observed but affected males rarely reproduce as a result of various urogenital anomalies.

A somewhat similar X-linked syndrome of microphthalmia, sometimes called OFCD syndrome (syndromic 2 microphthalmia; 300166) has been reported to be caused by mutations in BCOR (Xp11.4).  This MCOPS2 disorder is often considered to be X-linked dominant with lethality in males.

Another X-linked non-syndromic form of microphthalmia with colobomas has been reported (Microphthalmia with Coloboma, X-Linked; 300345).  In addition there is a similar disorder of simple Microphthalmia with Coloboma that is inherited either in an autosomal dominant or autosomal recessive pattern (605738, 610092, 611638, 613703, 251505 ).

Pedigree: 
X-linked recessive, carrier mother
X-linked recessive, father affected
Treatment
Treatment Options: 

There is no treatment beyond supportive care for specific health issues. 

References
Article Title: 

Fucosidosis

Clinical Characteristics
Ocular Features: 

Retinal and conjunctival vessels may appear tortuous, dilated, and irregular in diameter, characteristics sometimes seen in Fabry disease.  Diffuse opacities may be seen in the superficial cornea but do not have the whorl-like pattern seen in Fabry disease.  The majority of ocular cells contain cytoplasmic, membrane-bound aggregates of fibrillogranular and multilaminated material.  The orbits may be shallow as a result of bony dysplasia of the cranial bones. 

Systemic Features: 

The coarse facial features have been described as "Hurler-like".  Two major types have been described: type 1 with onset in the first 6 months of life and rapid psychomotor and general neurologic deterioration, and the later onset, less severe type 2 in which angiokeratomas resembling Fabry disease occur.  Infants with type 1 may not survive beyond one year of age.  The Hurler-like face is less pronounced and the neurologic deterioration is less rapid in type 2 with survival often into the third decade or later.  The intracellular accumulation of glycolipids and glycoproteins leads to cell death accounting for the progression of CNS disease.   Abnormal bone growth (dysostosis multiplex) can lead to short stature.  Elevated sweat NaCl, hypohidrosis, and poor temperature control can be a feature of both types but this is more pronounced in type 1.  The DNA mutation is the same in both types and there may be overlap in some of the clinical features.  Furthermore, both types have been reported in the same family.

Low levels of alpha-L-fucosidase can be detected in plasma, urine, and leukocytes.  Glycolipids and glycoproteins have also been shown to accumulate in the cells of the skin, liver, spleen, pancreas and kidneys. 

Genetics

Fucosidosis is a rare, progressive, autosomal recessive, lysosomal storage disease in which fucose accumulates in tissue as a result of defective alpha-L-fucosidase.  The responsible mutations are found in the FUCA1 gene (1p34). 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for the primary disease.  A multidisciplinary supportive program can be beneficial for some patients.  Respiratory therapy especially is important to reduce the threat of infections.

References
Article Title: 

Fucosidosis revisited: a review of 77 patients

Willems PJ, Gatti R, Darby JK, Romeo G, Durand P, Dumon JE, O'Brien JS. Fucosidosis revisited: a review of 77 patients. Am J Med Genet. 1991 Jan;38(1):111-31. Review.

PubMed ID: 
2012122

Adrenoleukodystrophy, Autosomal

Clinical Characteristics
Ocular Features: 

This early onset and rapidly progressive form of adrenoleukodystrophy is rare.  The early onset and rapidly fatal course of the disease has limited full delineation of the ocular features.  The most striking is the presence of 'leopard-spots' pigmentary changes in the retina.  Polar cataracts, strabismus, and epicanthal folds have also been reported. 

Systemic Features: 

Onset of symptoms occurs shortly after birth often with seizures and evidence of psychomotor deficits.  Rapid neurologic deterioration begins at about 1 year of age with death usually by the age of 3 years.  Hyperpigmentation of the skin may be apparent a few months after birth.  Opisthotonus has been observed.  The ears may be low-set, the palate is highly arched, and the nostrils anteverted.  Frontal bossing may be present.  Serum pipecolic acid and very-long-chain fatty acids (VLCFAs) can be markedly elevated.  Cystic changes in the kidneys have been reported. 

Genetics

This is an autosomal recessive peroxismal disorder resulting from homozygous mutations in receptor gene mutations such as PEX1, PEX5, PEX13, and PEX26.

There is also an X-linked recessive adrenoleukodystrophy (300100) sometimes called ALD but it lacks some of the morphologic features and is somewhat less aggressive. 

Neonatal adrenoleukodystrophy along with infantile Refsum disease (266510, 601539) and Zellweger syndrome (214100) are now classified as Zellweger spectrum or perioxismal biogenesis disorders.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Treatment is mainly supportive for associated health problems. 

References
Article Title: 

Sandhoff Disease

Clinical Characteristics
Ocular Features: 

Retinal ganglion cells are rendered dysfunctional from the toxic accumulation of intra-lysosomal GM2 ganglioside molecules causing early visual symptoms.  These cells in high density around the fovea centralis create a grayish-white appearance.  Since ganglion cells are absent in the foveolar region, this area retains the normal reddish appearance, producing the cherry-red spot.  Axonal decay and loss of the ganglion cells leads to optic atrophy and blindness. 

Systemic Features: 

Sandhoff disease may be clinically indistinguishable from Tay-Sachs disease even though the same enzyme is defective (albeit in separate subunits A and B that together comprise the functional enzymes).  The presence of hepatosplenomegaly in Sandoff disease may be distinguishing. The infantile form of this lysosomal storage disease seems to be the most severe.  Infants appear to be normal until about 3-6 months of age when neurological development slows and muscles become weak.  Seizures, loss of interest, and progressive paralysis begin after this together with loss of vision and hearing.  An exaggerated startle response is considered an early and helpful sign in the diagnosis.  Among infants with early onset disease, death usually occurs by 3 or 4 years of age.   

Ataxia with spinocerebellar degeneration, motor neuron disease, dementia, and progressive dystonia are more common in individuals with later onset of neurodegeneration.  The juvenile and adult-onset forms of the disease also progress more slowly.  

Genetics

Sandhoff disease results from mutations in the beta subunit of the hexosaminidase A and B enzymes.  It is an autosomal recessive disorder caused by mutations in HEXB (5q13). 

Tay-Sachs disease (272800) can be clinically indistinguishable from Sandoff disease and they are allelic disorders.  However, the mutation in Tay-Sachs (272800) is in HEXA resulting in dysfunction of the alpha subunit of hexosaminidase A enzyme. 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No specific treatment is available beyond general support with proper nutrition and maintainence of airways.  Anticonvulsants may be helpful in some stages.  Gene therapy in fibroblast cultures has achieved some restoration of  hexosaminidase A activity in Tay-Sachs disease and may have potential in Sandhoff disease as well. 

References
Article Title: 

RAB18 Deficiency

Clinical Characteristics
Ocular Features: 

Microphthalmia with microcornea, lens opacities, small and unresponsive pupils, and optic atrophy are the outstanding ocular features of this syndrome.  The eyes appear deeply set.  Some but not all have ERG evidence of rod and cone dysfunction.  The VEP is usually abnormal.  Short palpebral fissures have been described. 

Systemic Features: 

Patients with the micro syndrome have many somatic and neurologic abnormalities.  Infants usually have feeding problems that is sometimes accompanied by gastroesophageal reflux.  Some degree of psychomotor retardation and developmental delays is common.  Both spasticity and hypotonia have been described.  Some patients have seizures.  Facial hypertrichosis, anteverted ears, and a broad nasal bridge are often noted.   There may be absence of the corpus callosum while diffuse cortical and subcortical atrophy, microgyria, and pachygyria may be evident on MRI imaging.  Hypogenitalism may be a feature in both sexes.  Males may also have cryptorchidism and a micropenis while females can have hypoplasia of the labia minora and clitoris and a small introitus.  Microcephaly is inconsistently present. 

Genetics

This is a clinically and genetically heterogeneous disorder caused by homozygous mutations in at least 4 genes: RAB3GAP1 (WARBM1), RAB3GAP2 (WARBM2), RAB18 (WARBM3), and TBC1D20 (WARBM4).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment is available.  Vision remains subnormal even after cataracts are removed.  Nutrition may be improved with placement of a gastrostomy tube.

References
Article Title: 

New RAB3GAP1 mutations in patients with Warburg Micro Syndrome from different ethnic backgrounds and a possible founder effect in the Danish

Morris-Rosendahl DJ, Segel R, Born AP, Conrad C, Loeys B, Brooks SS, M?oller L,Zeschnigk C, Botti C, Rabinowitz R, Uyanik G, Crocq MA, Kraus U, Degen I, Faes F. New RAB3GAP1 mutations in patients with Warburg Micro Syndrome from different ethnic backgrounds and a possible founder effect in the Danish. Eur J Hum Genet. 2010 Oct;18(10):1100-6.

PubMed ID: 
20512159

Sanfilippo Syndrome (MPS IIIA, B, C, D)

Clinical Characteristics
Ocular Features: 

This form of mucopolysaccharidosis causes little or no corneal clouding.  Abnormal retinal pigmentation can be seen.

Systemic Features: 

Sanfilippo syndrome differs from other forms of mucopolysaccharidoses in the severity of the neurologic degeneration compared to the amount of somatic disease.  Infants usually appear healthy but developmental delay becomes evident by 2 or 3 years of age and physical growth slows.  Deterioration in mental development is progressive and seizures occur in some.  Gait and speech are impaired and by age 10 years patients have severe disabilities.  Behavioral problems including hyperactivity and aggression are often severe.

There is some hepatosplenomegaly, mild coarseness of the facial features, claw hands and mild bony changes such as biconvexity of the vertebral bodies and thick calvaria.  Hirsutism and synophrys are common.  The hair is unusually coarse.  Joints are frequently stiff and more severely affected individuals may have hearing loss.  Diarrhea is frequently a problem and most patients have some airway obstruction and are susceptible to recurrent respiratory infections.  Some patients have cardiovascular problems.

Genetics

MPS III is a lysosomal storage disease and may be caused by mutations in 1 of 4 genes that result in defective enzymes unable to break down mucopolysaccharides (glycosaminoglycans).  MPS IIIA (252900)results from a defect in the heparan sulfate sulfatase gene SGSH (17q25.3), type IIIB (252920)from a defect in the N-acetyl-alpha-D-glucosaminidase gene NAGLU (17q21), type IIIC (252930) from a defect in the acetyl-CoA:alpha-glucosaminide acetyltransferase gene HGSNAT (8p11.1), and type IIID (252940) from a defect in the N-acetylglucosamine-6-sulfatase gene GNS (12q14).  Heparan sulfate is excreted in all types.  Because of their clinical similarities these are discussed as a group in this database.  All are inherited in autosomal recessive patterns.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no treatment for the underlying disease.  Therapy is primarily supportive.  A multidisciplinary approach with neurologists, ophthalmologists, audiologists, cardiologists, gastroenterologists, and orthopedists is most likely to result in treatments that can improve quality of life.

References
Article Title: 

Cohen Syndrome

Clinical Characteristics
Ocular Features: 

Patients have early onset night blindness with defective dark adaptation and corresponding ERG abnormalities.  Visual fields are constricted peripherally and central visual acuity is variably reduced.  A pigmentary retinopathy is often associated with a bull’s eye maculopathy. The retinopathy is progressive as is high myopia.  The eyebrows and eyelashes are long and thick and the eyelids are highly arched and often ‘wave-shaped’.  Congenital ptosis, optic atrophy, and ectopia lentis have also been reported.

Systemic Features: 

Affected individuals have a characteristic facial dysmorphism in which ocular features play a role.  They have a low hairline, a prominent nasal root, and a short philtrum.  The tip of the nose appears bulbous. The head circumference is usually normal at birth but lags behind in growth so that older individuals appear microcephalic.  Delays in developmental milestones are noticeable in the first year of life.  Mild to moderate mental retardation is characteristic but does not progress.  Hypotonia is common early, and many individuals are short in stature.  Low white counts and frank neutropenia are often seen and some patients have frequent infections, especially of the oral mucosa and the respiratory tract.  A cheerful disposition is said to be characteristic.

Genetics

This is an autosomal recessive disorder caused by a mutation in the COH1 (VPS13B) gene on chromosome 8 (8q22-q23).  However, a variety of mutations have been reported including deletions and missense substitutions and, since these are scattered throughout the gene, complete sequencing is necessary before a negative result can be confirmed.

There is evidence of significant clinical heterogeneity between cohorts descended from different founder mutations.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Corrective lenses for myopia can be helpful.  For patients with sufficient vision, low vision aids can be helpful.  Selected individuals may benefit from vocational and speech therapy.  Infections should be treated promptly.

References
Article Title: 

Cohen syndrome is caused by mutations in a novel gene, COH1, encoding a transmembrane protein with a presumed role in vesicle-mediated sorting and intracellular protein transport

Kolehmainen J, Black GC, Saarinen A, Chandler K, Clayton-Smith J, Traskelin AL, Perveen R, Kivitie-Kallio S, Norio R, Warburg M, Fryns JP, de la Chapelle A, Lehesjoki AE. Cohen syndrome is caused by mutations in a novel gene, COH1, encoding a transmembrane protein with a presumed role in vesicle-mediated sorting and intracellular protein transport. Am J Hum Genet. 2003 Jun;72(6):1359-69.

PubMed ID: 
12730828

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