strabismus

Foveal Hypoplasia 2

Clinical Characteristics
Ocular Features: 

The cardinal feature in this condition is foveal hypoplasia which is characterized by the lack of a foveal depression and continuity of all neurosensory layers across the foveal area as revealed by OCT.  This is accompanied by poor visual acuity, nystagmus, and strabismus.  Hypopigmentation of the immediate area has also been reported in some patients.  Visual acuity in one study of 9 patients ranged from 20/50 to 20/200.  The ERG and flash VEP can be normal.  Color vision has been described as normal in some individuals.

Dysgenesis of the anterior segment seems to be family-specific and consists of Axenfeld anomaly or embryotoxon.

Systemic Features: 

In most cases the only features are foveal hypoplasia with or without anterior chamber anomalies.  Three affected sisters in one family were reported to have mild developmental delay.

Genetics

Homozygous mutations in SLC38A8 (16q23.3) are responsible for this disorder. 

For a somewhat similar condition of foveal hypoplasia see FVH1 (136520), which is, however, caused by a different mutation and inherited in an autosomal dominant pattern.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no known treatment.

References
Article Title: 

Hypotonia, Infantile, with Psychomotor Retardation And Characteristic Facies 1

Clinical Characteristics
Ocular Features: 

Nystagmus, strabismus and sometimes optic atrophy have been noted.  Poor fixation may be present.   

Systemic Features: 

This progressive disorder can be evident at birth based on the facial dysmorphism.  The face is triangular, the forehead is prominent, the nose is small, the ears appear large and low-set.  The mouth appears wide with a thin upper lip.  Early development may be near normal for the first 6 months but thereafter psychomotor regression and slow physical growth are evident.  Patients have microcephaly and seldom achieve normal milestones.  Spasticity in the extremities and truncal hypotonia with distal muscle atrophy are evident.  The face appears triangular, the forehead is prominent, the nose is small, and the ears appear large and low-set.  Pectus carinatum and pes varus may be present.   Males often have cryptorchidism.

Brain imaging has revealed cerebellar atrophy and "while matter abnormalities".  Sural nerve biopsies show evidence of infantile neuroaxonal dystrophy.

Some individuals are less severely affected, retain the ability to speak, and are able to walk at least into the second decade of life.

Genetics

Based on transmission patterns this condition is inherited as an autosomal recessive disorder caused by mutations in in the NALCN gene (13q32.3-q33.1.

For somewhat similar disorders caused by mutations in other genes see IHPRF2 (616801) and IHPRF3 (616900).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Cerebellar Atrophy, Visual Impairment, and Psychomotor Retardation

Clinical Characteristics
Ocular Features: 

Patients usually have deep-set eyes.  Cortical visual impairment has been described in one patient but optic atrophy has been seen in another.  The VEP and ERG are described as 'abnormal'.  Strabismus, hyperopia, and myopia are sometimes seen.

Systemic Features: 

Progressive microcephaly is often noted.  Truncal hypotonia and scoliosis may be present while muscle tone is increased in the extremities in the presence of diminished deep tendon reflexes in other patients.  Dystonic posturing occurs in some families.  Gingival hyperplasia is a common feature and retrognathia is often present.

Brain imaging reveals progressive cerebellar atrophy and a foreshortened corpus callosum in all families.  Various degrees of cerebral atrophy have been identified while intellectual disability may be marked.  Speech delay is common.

Genetics

This is an autosomal recessive condition associated with homozygous mutations in the EMC1 gene (1p36.13).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatnent has been reported.

References
Article Title: 

Monoallelic and Biallelic Variants in EMC1 Identified in Individuals with Global Developmental Delay, Hypotonia, Scoliosis, and Cerebellar Atrophy

Harel T, Yesil G, Bayram Y, Coban-Akdemir Z, Charng WL, Karaca E, Al Asmari A, Eldomery MK, Hunter JV, Jhangiani SN, Rosenfeld JA, Pehlivan D, El-Hattab AW, Saleh MA, LeDuc CA, Muzny D, Boerwinkle E; Baylor-Hopkins Center for Mendelian Genomics, Gibbs RA, Chung WK, Yang Y, Belmont JW, Lupski JR. Monoallelic and Biallelic Variants in EMC1 Identified in Individuals with Global Developmental Delay, Hypotonia, Scoliosis, and Cerebellar Atrophy. Am J Hum Genet. 2016 Mar 3;98(3):562-70.

PubMed ID: 
26942288

Corpus Callosum Agenesis with Facial Anomalies and Cerebellar Ataxia

Clinical Characteristics
Ocular Features: 

The thick, bushy eyebrows and long eyelashes are part of the generalized hirsutism.  The eyelids appear puffy.  Strabismus of unknown type has been reported.

Systemic Features: 

Infants are hypertonic at birth but this seems to be less evident as they grow.  Slow physical growth and psychomotor delay are common.  The skull in newborns is small.  The ears are low-set, protruding, and posteriorly rotated.  The nostrils are anteverted and the lower lip protrudes.  There are severe cognitive defects which has been called mental retardation.  Speech is poor or may never develop.  Cerebellar ataxia and uncoordinated hand movements are features.  Brain imaging reveals cerebellar hypoplasia and some degree of corpus callosum agenesis including absence.

Genetics

Homozygous mutations in the FRMD4A gene (10p13) have been found to segregate with this disorder in a large consanguineous Bedouin kindred.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Hyperphosphatasia with Mental Retardation Syndrome 6

Clinical Characteristics
Ocular Features: 

Congenital cataracts may be present.  The eyes appear deeply-set and strabismus has been seen in severely affected cases.   

Systemic Features: 

Two families have been reported.  The range of severity in symptoms is wide.  Birth may occur prematurely especially in the presence of polyhydramnios.  Postnatal development can be complicated by seizures, chronic lung disease, developmental regression, and renal disease.  Poor growth secondary to feeding difficulties have been reported.  Death can occur in early childhood.

Dysmorphic features include a short neck, bitemporal narrowing, depressed nasal bridge, and proximal limb shortening.  Osteopenia, flexion contractures, and hip dysplasia may be present.  Dilatation of the renal collecting system with increased echogenicity have been reported.  Creatine kinase and serum alkaline phosphatase may be increased and muscle histology shows small, atrophic fibers with increased fibrosis and considerable variations in fiber size.

Genetics

Homozygous mutations in the PIGY gene (4q22.1) resulting in deficiencies of glycosylphosphatidylinositol synthesis have been associated with this condition.  

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment has been reported.

References
Article Title: 

Mutations in PIGY: expanding the phenotype of inherited glycosylphosphatidylinositol deficiencies

Ilkovski B, Pagnamenta AT, O'Grady GL, Kinoshita T, Howard MF, Lek M, Thomas B, Turner A, Christodoulou J, Sillence D, Knight SJ, Popitsch N, Keays DA, Anzilotti C, Goriely A, Waddell LB, Brilot F, North KN, Kanzawa N, Macarthur DG, Taylor JC, Kini U, Murakami Y, Clarke NF. Mutations in PIGY: expanding the phenotype of inherited glycosylphosphatidylinositol deficiencies. Hum Mol Genet. 2015 Nov 1;24(21):6146-59.

PubMed ID: 
26293662

Immunodeficiency-Centromeric Instability-Facial Anomalies Syndrome 3

Clinical Characteristics
Ocular Features: 

Patients have been described as having variable oculofacial features including epicanthal folds, hypertelorism, strabismus, and 'tapetoretinal degeneration'.    

Systemic Features: 

The full phenotype is variable and unknown based on the 5 reported patients from 4 families of whom 3 were consanguineous.  Recurrent infections (especially respiratory and otitis media) seem to be among the most consistent features.  Others include intrauterine growth retardation, developmental delay including psychomotor delays, a flat midface with various anomalies, low-set ears, renal dysgenesis, polydactyly, severe agammaglobulinemia, hypospadias, and cryptorchidism.  Normal T-cell function and normal B cells are present.  Conductive hearing loss, polydactyly, and scoliosis may be features as well.  Two of the 5 reported patients with ICF3 were reported to have mental retardation.  One patient died at the age of 26 years.

Genetics

Homozygosity of CDCA7 (2q31.1) mutations with centromeric instability and hypomethylation of selected juxtacentromeric heterochromatin regions is responsible for this (ICF3) autosomal recessive condition.  There is genetic heterogeneity in ICF (ICF1, ICF2, ICF3, and ICF4 [see 242860).   

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment has been reported.

References
Article Title: 

Mutations in CDCA7 and HELLS cause immunodeficiency-centromeric instability-facial anomalies syndrome

Thijssen PE, Ito Y, Grillo G, Wang J, Velasco G, Nitta H, Unoki M, Yoshihara M, Suyama M, Sun Y, Lemmers RJ, de Greef JC, Gennery A, Picco P, Kloeckener-Gruissem B, Gungor T, Reisli I, Picard C, Kebaili K, Roquelaure B, Iwai T, Kondo I, Kubota T, van Ostaijen-Ten Dam MM, van Tol MJ, Weemaes C, Francastel C, van der Maarel SM, Sasaki H. Mutations in CDCA7 and HELLS cause immunodeficiency-centromeric instability-facial anomalies syndrome. Nat Commun. 2015 Jul 28;6:7870.

PubMed ID: 
26216346

Hypotonia, Infantile, with Psychomotor Retardation

Clinical Characteristics
Ocular Features: 

Abducens nerve palsy with characteristic strabismus (esotropia) can be present.

Systemic Features: 

Mothers may note decreased fetal movements.  Severe generalized hypotonia can be evident at birth, requiring tube feeding and respiratory assistance.  Death may occur before 6 months of age but with intense supportive care children can live for several years.  Brain imaging may show enlarged lateral ventricles and thinning of the corpus callosum in some individuals but no abnormalities in others.  Muscle biopsies can show severe myopathic changes with increased fibrosis, variation in fiber size, and small atrophic fibers.  Cardiac septal defects have been reported.  Delayed psychomotor development is a common feature.

Genetics

Homozygous mutations in the CCDC174 gene (3p25.1) are responsible for this condition so far reported in only two families with 6 children affected.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is known for this condition.

References
Article Title: 

CDC174, a novel

Volodarsky M, Lichtig H, Leibson T, Sadaka Y, Kadir R, Perez Y, Liani-Leibson
K, Gradstein L, Shaco-Levy R, Shorer Z, Frank D, Birk OS. CDC174, a novel
component of the exon junction complex whose mutation underlies a syndrome of
hypotonia and psychomotor developmental delay
. Hum Mol Genet. 2015 Nov
15;24(22):6485-91.

PubMed ID: 
26358778

Spastic Paraplegia with Psychomotor Retardation and Seizures

Clinical Characteristics
Ocular Features: 

The eyes are usually deeply set.  Nothing is known regarding visual acuity.  Strabismus is a common feature.  Retinal dystrophy (not further described) has been reported in 4 of 8 patients described.  The ERG in one individual was read as consistent with cone-rod dystrophy.

Systemic Features: 

Newborns are hypotonic and severe psychomotor retardation is evident a few months later.  Truncal ataxia and progressive lower limb spasticity are seen later.  Mobility is significantly impaired and many individuals are confined to bed or a wheelchair and never walk.  Dysarthria is frequently present and some individuals have a neurosensory hearing loss.  Myoclonic seizures may be evident.  Kyphoscoliosis, macrocephaly, and various foot deformities have been described.

CT scans of the brain may show generalized cerebral atrophy and a hypoplastic corpus callosum.  The ventricles may be enlarged and the EEG confirms the occurrence of myoclonic as well as tonic-clonic and focal epilepsy.

Genetics

This is an autosomal recessive disorder caused by homozygous or compound heterozygous mutations in the HACE1 gene (6q16).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported for this condition but physical therapy and assistive devices such as hearing and visual aids may be helpful.

References
Article Title: 

DDD study. Discovery of four recessive developmental disorders using probabilistic genotype and phenotype matching among 4,125 families

Akawi N, McRae J, Ansari M, Balasubramanian M, Blyth M, Brady AF, Clayton S, Cole T, Deshpande C, Fitzgerald TW, Foulds N, Francis R, Gabriel G, Gerety SS, Goodship J, Hobson E, Jones WD, Joss S, King D, Klena N, Kumar A, Lees M, Lelliott C, Lord J, McMullan D, O'Regan M, Osio D, Piombo V, Prigmore E, Rajan D, Rosser E, Sifrim A, Smith A, Swaminathan GJ, Turnpenny P, Whitworth J, Wright CF, Firth HV, Barrett JC, Lo CW, FitzPatrick DR, Hurles ME; DDD study. Discovery of four recessive developmental disorders using probabilistic genotype and phenotype matching among 4,125 families. Nat Genet. 2015 Nov;47(11):1363-9.

PubMed ID: 
26437029

HACE1 deficiency causes an autosomal recessive neurodevelopmental syndrome

Hollstein R, Parry DA, Nalbach L, Logan CV, Strom TM, Hartill VL, Carr IM, Korenke GC, Uppal S, Ahmed M, Wieland T, Markham AF, Bennett CP, Gillessen-Kaesbach G, Sheridan EG, Kaiser FJ, Bonthron DT. HACE1 deficiency causes an autosomal recessive neurodevelopmental syndrome. J Med Genet. 2015 Dec;52(12):797-803.

PubMed ID: 
26424145

Cleft Palate, Psychomotor Retardation, and Distinctive Facial Features

Clinical Characteristics
Ocular Features: 

The facial dysmorphism is present at birth together with the cleft palate.  Downslanting lid fissures, widely spaced eyes, and ptosis may be present.  Eyebrows have been described as sparse in one patient.  Strabismus and ocular apraxia are present in some children. 

Systemic Features: 

Three patients have been reported, one of whom also had a second deletion in a gene implicated in the Kabuki syndrome.  This individual had hypertrichosis and synophyrys whereas the others had sparse eyebrow and temporal hair.  The teeth are malformed with some conically shaped and widely spaced.  The forehead is prominent and the fingers are tapered and brachydactylous with 5th finger clinodactyly.

There are significant delays in achieving developmental milestones.  Hypotonia has been described.  Speech and walking in particular may be delayed for several years.   Physical growth may be delayed as well.  A variety of brain anomalies have been seen in some but not all individuals.  Hypospadius and cryptorchidism have been described.  All children reported have palatal anomalies.

Genetics

Heterozygous mutations in the KDM1A gene have been identified in two patients.  In another report a single patient had an out-of-frame 3-nucleotide deletion in the ANKRD11 gene (as sometimes found in Kabuki syndrome) plus a mutation in the KDM1A gene. 

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment is known.

References
Article Title: 

Gene discovery for Mendelian conditions via social networking: de novo variants in KDM1A cause developmental delay and distinctive facial features

Chong JX, Yu JH, Lorentzen P, Park KM, Jamal SM, Tabor HK, Rauch A, Saenz MS, Boltshauser E, Patterson KE, Nickerson DA, Bamshad MJ. Gene discovery for Mendelian conditions via social networking: de novo variants in KDM1A cause developmental delay and distinctive facial features. Genet Med. 2015 Dec 10. doi: 10.1038/gim.2015.161. [Epub ahead of print].

PubMed ID: 
26656649

Infantile Cerebellar-Retinal Degeneration

Clinical Characteristics
Ocular Features: 

Visual tracking can be normal during the newborn period but lack of visual fixation and attention soon become evident.  Strabismus, nystagmus, and abnormal pursuit movements are often present.  Optic atrophy has been reported as early as 3 years of age.  VEP and ERG responses are extinguished in the first two years. The nystagmus may be multidirectional.  Acuity loss seems to be progressive.  A progressive retinal degeneration (not further characterized) has been reported.

Systemic Features: 

Infants generally appear normal at birth.  Within the first 6 months they show signs of developmental delay and neurological signs such as truncal hypotonia, seizures, athetosis and head bobbing.  Milestones of sitting, rolling over, and reactions to others are seldom achieved.  Cerebellar brain imaging shows progressive atrophy in all patients and some have cortical atrophy as well.  Some patients have evidence of hearing loss.   Severe failure to thrive and psychomotor delays are usually present.  Death may occur within several months of birth although some live for several decades.

Genetics

This condition results from homozygous or compound heterozygous mutations in the ACO2 gene (22q13.2).  The mutation has also been associated with optic atrophy 9 (616289).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment beyond supportive care is known.

References
Article Title: 

Mutations in the tricarboxylic acid cycle enzyme, aconitase 2, cause either isolated or syndromic optic neuropathy with encephalopathy and cerebellar atrophy

Metodiev MD, Gerber S, Hubert L, Delahodde A, Chretien D, Gerard X, Amati-Bonneau P, Giacomotto MC, Boddaert N, Kaminska A, Desguerre I, Amiel J, Rio M, Kaplan J, Munnich A, Rotig A, Rozet JM, Besmond C. Mutations in the tricarboxylic acid cycle enzyme, aconitase 2, cause either isolated or syndromic optic neuropathy with encephalopathy and cerebellar atrophy. J Med Genet. 2014 Dec;51(12):834-8.

PubMed ID: 
25351951

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