autosomal recessive

PEHO Syndrome

Clinical Characteristics
Ocular Features: 

Optic atrophy is a common feature.  There may be lack of visual fixation from birth or sometimes several months later, attributed to cortical inattention.  Flash visual evoked potentials may be unrecordable. Pupillary responses to light are 'weak' and sluggish. Epicanthal folds may be seen.

Systemic Features: 

Infants are usually born with a normal head circumference but fall behind (2 SD or more) in the first year.  They have neonatal and infantile central hypotonia with brisk peripheral tendon reflexes during early childhood.  They are sometimes described as drowsy or lethargic.  Facial and limb edema can be extensive but transient sometimes and can disappear later in childhood.  The fingers are tapered.  The cheeks are full, the mouth is usually open and the upper lip appears 'tented'.  Global developmental delay is common and normal milestones are seldom attained.  Some patients have been described as severely retarded mentally.  Infantile spasms and myoclonic jerkingcan be seen within the first months of life while frank seizures with hypsarrhythmia are common in the first year of life.  Status epilepticus is a common occurrence.  General drowsiness and poor feeding are often features.  Death usually occurs in infancy or early childhood.  Midface hypoplasia and micrognathia are often present.

Brain imaging (MRI) and histology show severe alterations in myelination and cellular organization.  Neuronal loss is seen in the inner granular layer of the cerebellum but there is relative preservation of Purkinje cells.  General and progressive atrophy of the cerebellum and brain stem have been described.

Genetics

Homozygous frameshift mutations in ZNHIT3 (17q12) have been identified in affected members of several consanguineous families.  The presumed mutation seems to be most prevalent in Finland.

A somewhat similar disorder known as PEHO-like syndrome (617507) is the result of homozygous mutations in the CCDC88A gene.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Physical therapy to prevent contractures and general supportive care can be helpful.  Supplemental feeding may be required. 

References
Article Title: 

The PEHO syndrome

Riikonen R. The PEHO syndrome. Brain Dev. 2001 Nov;23(7):765-9. Review.

PubMed ID: 
11701291

Pontocerebellar Hypoplasia 3

Clinical Characteristics
Ocular Features: 

Optic atrophy is an inconsistent feature (sometimes even unilateral) of patients with PCH.  Cortical blindness has also been described.  There may be dysmorphic facial features such as wide palpebral fissures, epicanthal folds, and prominent eyes. 

Systemic Features: 

Infants are generally small and hypotonic at birth.  The skull is small and often brachycephalic.  The ears are large and low-set and  facial dysmorphism (full cheeks, long philtrum) is present.  Infants have poor head control and truncal ataxia.  Later, hyperreflexia and spasticity become evident.  Seizures are common.  Developmental delays, both somatic and mental, are nearly universal and large joint contractures are often seen. Many of these signs are progressive.  

Brain imaging generally reveals cerebral and cerebellar atrophy, a hypoplastic corpus callosum, a small cerebellar vermis, and a hypoplastic brainstem.  Short stature is a feature and early death often occurs.

Genetics

PCH3 is one of at least 10 syndromes belonging to a clinically and genetically heterogeneous group of conditions known as pontocerebellar hypoplasias.  Members of this group, while individually rare, nevertheless collectively account for a significant proportion of what was once labeled cerebral palsy.

PCH3 results from homozygous mutations in the PCLO gene (7q21). 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for the general disorder.

References
Article Title: 

Loss of PCLO function underlies pontocerebellar hypoplasia type III.

Ahmed MY, Chioza BA, Rajab A, Schmitz-Abe K, Al-Khayat A, Al-Turki S, Baple EL, Patton MA, Al-Memar AY, Hurles ME, Partlow JN, Hill RS, Evrony GD, Servattalab S, Markianos K, Walsh CA, Crosby AH, Mochida GH. Loss of PCLO function underlies pontocerebellar hypoplasia type III. Neurology. 2015 Apr 28;84(17):1745-50.

PubMed ID: 
25832664

Cataracts 13, Congenital, in Adult i RBC Phenotype

Clinical Characteristics
Ocular Features: 

The only ocular signs are dense nuclear cataracts with vision in the range of count fingers or light perception.  The opacities are usuallyrecognized at birth.  Some patients develop nystagmus. 

Systemic Features: 

The Ii blood group is associated with cataracts, most strongly in Asians.  The RBC antigens are developmentally regulated.  Fetal and neonatal RBCs express the i form of the antigen which is gradually converted enzymatically to the I form that normally persists in adults.  The normal Ii adult phenotype is reached before the age of two years. 

Genetics

Homozygous or compound heterozygous deletions of the GCNT2 gene (6p24.3) produce the adult i phenotype (110800) which may or may not be associated with lens opacities.

The GCNT2 gene codes for 3 variants of its product. Mutations that eliminate all 3 GCNT2 variants result in the adult i phenotype in association with congenital cataracts.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Surgery to remove the cataracts may be indicated in some individuals.

References
Article Title: 

Deletion at the GCNT2 Locus Causes Autosomal Recessive Congenital Cataracts

Irum B, Khan SY, Ali M, Daud M, Kabir F, Rauf B, Fatima F, Iqbal H, Khan AO, Al Obaisi S, Naeem MA, Nasir IA, Khan SN, Husnain T, Riazuddin S, Akram J, Eghrari AO, Riazuddin SA. Deletion at the GCNT2 Locus Causes Autosomal Recessive Congenital Cataracts. PLoS One. 2016 Dec 9;11(12):e0167562.

PubMed ID: 
27936067

3-methylglutaconic Aciduria with Cataracts, Neurologic Involvement and Neurtropenia

Clinical Characteristics
Ocular Features: 

Descriptions of ocular findings have been limited.  Congenital nuclear cataracts have been described in one patient but lens opacities have been noted in others.

Systemic Features: 

There is considerable heterogeneity in the phenotype with some patients having minimal signs and living to adulthood whereas others succumb to their disease in the first year of life.  The onset of progressive encephalopathy usually occurs in infancy as evidenced by various movement abnormalities and psychomotor delays.  Neonatal hypotonia sometimes progresses to spasticity.  However, other infants are neurologically normal.  Delayed psychomotor development, ataxia, seizures, and dystonia may be seen.  Brain imaging may reveal cerebellar and cerebral atrophy along with brain stem abnormalities.  Neuronal loss, diffuse gliosis, and microvacuolization have been seen on neuropathologic examination.  Dysphagia is common.  Severe neutropenia and recurrent infections may begin in infancy as well.

Increased amounts of 3-methylglutaconic acid are found in the urine while the bone marrow may contain evidence of arrested granulopoiesis. 

Genetics

This autosomal recessive disorder results from homozygous or compound heterozygous mutations in the CLPB gene (11q13.4).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment has been reported for this condition.

References
Article Title: 

CLPB mutations cause 3-methylglutaconic aciduria, progressive brain atrophy, intellectual disability, congenital neutropenia, cataracts, movement disorder

Wortmann SB, Zietkiewicz S, Kousi M, Szklarczyk R, Haack TB, Gersting SW, Muntau AC, Rakovic A, Renkema GH, Rodenburg RJ, Strom TM, Meitinger T, Rubio-Gozalbo ME, Chrusciel E, Distelmaier F, Golzio C, Jansen JH, van Karnebeek C, Lillquist Y, Lucke T, Ounap K, Zordania R, Yaplito-Lee J, van Bokhoven H, Spelbrink JN, Vaz FM, Pras-Raves M, Ploski R, Pronicka E, Klein C, Willemsen MA, de Brouwer AP, Prokisch H, Katsanis N, Wevers RA. CLPB mutations cause 3-methylglutaconic aciduria, progressive brain atrophy, intellectual disability, congenital neutropenia, cataracts, movement disorder. Am J Hum Genet. 2015 Feb 5;96(2):245-57.

PubMed ID: 
25597510

Nemaline Myopathy 10

Clinical Characteristics
Ocular Features: 

Ophthalmoplegia has been reported in 29% of patients.

Systemic Features: 

In this form of nemaline myopathy, polyhydramnios, weak or absent fetal movements, and joint contractures may be noted during the antenatal period.  Hypotonia and generalized weakness, respiratory difficulties, feeding difficulties and evidence of bulbar weakness may be noted at birth.  Many patients die of respiratory failure in the neonatal period but some may survive into the second decade. 

Cardiac function is normal.

Genetics

This autosomal recessive disorder results from homozygous or compound heterozygous mutations in the LMOD3 gene (3p14.1).  This gene is expressed in both skeletal and cardiac muscle and its product is essential for the organization of sarcomeric thin filaments in skeletal muscle.

Mutations in at least 10 genes cause nemaline myopathy.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No general treatment is available for this condition but supportive care such as respiratory assistance and feeding supplementation may be helpful.  Physical therapy and special education may be helpful.

References
Article Title: 

Leiomodin-3 dysfunction results in thin filament disorganization and nemaline myopathy

Yuen M, Sandaradura SA, Dowling JJ, Kostyukova AS, Moroz N, Quinlan KG, Lehtokari VL, Ravenscroft G, Todd EJ, Ceyhan-Birsoy O, Gokhin DS, Maluenda J, Lek M, Nolent F, Pappas CT, Novak SM, D'Amico A, Malfatti E, Thomas BP, Gabriel SB, Gupta N, Daly MJ, Ilkovski B, Houweling PJ, Davidson AE, Swanson LC, Brownstein CA, Gupta VA, Medne L, Shannon P, Martin N, Bick DP, Flisberg A, Holmberg E, Van den Bergh P, Lapunzina P, Waddell LB, Sloboda DD, Bertini E, Chitayat D, Telfer WR, Laquerriere A, Gregorio CC, Ottenheijm CA, Bonnemann CG, Pelin K, Beggs AH, Hayashi YK, Romero NB, Laing NG, Nishino I, Wallgren-Pettersson C, Melki J, Fowler VM, MacArthur DG, North KN, Clarke NF. Leiomodin-3 dysfunction results in thin filament disorganization and nemaline myopathy. J Clin Invest. 2014 Nov;124(11):4693-708. Erratum in: J Clin Invest. 2015 Jan;125(1):456-7.

PubMed ID: 
25250574

Peroxisomol Fatty Acyl-CoA Reductase 1 Disorder

Clinical Characteristics
Ocular Features: 

At least some patients have cataracts which may be congenital in origin.  Highly arched eyebrows are part of the facial dysmorphism.

Systemic Features: 

Neonatal hypotonia is common while postnatal psychomotor development, somatic growth delay, microcephaly, and seizures become evident later.  The coarse facial dysmorphism includes large ears, a flattened nasal root, thin upper lip, a long philtrum, and a flattening of the nasal root.  Cognitive deficits are often present and some individuals have significant mobility problems. 

Red blood cell plasmalogen may be decreased.

Genetics

This condition results from homozygous or compound heterozygous mutations in FAR1 gene (11p15.2) resulting in complete loss of enzyme activity consistent with a defect in peroxisomes.

There is some clinical resemblance to rhizomelic chondrodysplasia punctata (215100) in which congenital cataracts also occur but lacks the skeletal features and results from a different mutation. 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported for the generalized condition but physical therapy and special education could be helpful.  Cataract removal is an option that may be considered.

References
Article Title: 

Albinism, Oculocutaneous, Type V

Clinical Characteristics
Ocular Features: 

The phenotype in the two families studied includes photophobia, nystagmus, foveal hypoplasia and decreased visual acuity.  The fundus is hypopigmented.

Systemic Features: 

The hair is golden-colored and the skin is described as white. 

Genetics

The specific gene causing this form of oculocutaneous albinism has not been identified.  However, an area of homozygosity in the region of 4q24 has been identified in 6 members in two families belonging to a large consanguineous Pakistani pedigree in which it segregates with the OCA5 phenotype. 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for oculocutaneous albinism but appropriately tinted glasses could be beneficial.

References
Article Title: 

Increasing the complexity: new genes and new types of albinism

Montoliu L, Gronskov K, Wei AH, Martinez-Garcia M, Fernandez A, Arveiler B, Morice-Picard F, Riazuddin S, Suzuki T, Ahmed ZM, Rosenberg T, Li W. Increasing the complexity: new genes and new types of albinism. Pigment Cell Melanoma Res. 2014 Jan;27(1):11-18. Review.

PubMed ID: 
24066960

Chorioretinopathy with Microcephaly 3

Clinical Characteristics
Ocular Features: 

The eyes are not notably small although several patients have been reported to have significant hyperopia.  Vision can be impaired and some individuals have early-onset nystagmus.  The ERG responses are attenuated and may be absent.  The retina is dysplastic with multiple atrophic punched-out lesions, attenuated retinal vessels, and sparse pigmentation. Large retinal folds have been described and one patient developed a retinal detachment.  Optic atrophy was noted in one individual.

Systemic Features: 

Microcephaly of 3-4 standard deviations below normal is a constant feature.  Motor and language abilities can be mildly delayed and  several patients have had mild learning difficulties.   Brain imaging has been normal in most individuals but a shortened and thin corpus callosum was present in one patient.

Genetics

Family and genetic evidence suggest autosomal recessive inheritance.  Compound heterozygous mutations in the TUBGCP4 gene (15q15.3) code for part of a protein complex involved in microtubule organization.

For a somewhat similar condition with a different mutation involving the same microtubule complex see Chorioretinopathy with Microcephaly 1 (251270).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Low vision aids may be helpful in selected patients.

References
Article Title: 

Mutations in TUBGCP4 Alter Microtubule Organization via the γ-Tubulin Ring Complex in Autosomal-Recessive Microcephaly with Chorioretinopathy

Scheidecker S, Etard C, Haren L, Stoetzel C, Hull S, Arno G, Plagnol V, Drunat S, Passemard S, Toutain A, Obringer C, Koob M, Geoffroy V, Marion V, Strahle U, Ostergaard P, Verloes A, Merdes A, Moore AT, Dollfus H. Mutations in TUBGCP4 Alter Microtubule Organization via the g-Tubulin Ring Complex in Autosomal-Recessive Microcephaly with Chorioretinopathy. Am J Hum Genet. 2015 Apr 2;96(4):666-74.

PubMed ID: 
25817018

Alström Syndrome

Clinical Characteristics
Ocular Features: 

Progressive failure of rods and cones begins in the first year of life and inevitably leads to blindness.  Central vision is lost first and nystagmus in early childhood results.   Photophobia can be evident in the first year of life.  Early ERGs show severe impairment of cone responses with little or no rod dysfunction.  In the second and third decades all rod and cone responses are extinguished.  Vision can be less than 20/400 by the age of 10 years and usually all light perception is lost by the beginning of the third decade.  Pale optic nerves with retinal arteriorlar narrowing and posterior subcapsular cataracts have been seen.

Systemic Features: 

This is a multisystem disease with onset in the first year of life.  Infants may have a normal birth weight but develop truncal obesity in the first year.  Hearing loss is evident in the first decade.  Insulin resistant type 2 diabetes mellitus with hyperinsulinemia often occurs in childhood and may be accompanied by hypothyroidism and hypogonadotropic hypogonadism.  Acanthosis nigricans and some degree of pulmonary dysfunction are common.  The majority of individuals (70%) develop restrictive or dilated cardiomyopathy, many in the first months of life, resulting in cardiac failure.  The liver may become cirrhotic and renal failure occurs late.  Intelligence is usually normal but many patients (25-30%) have early delays in their developmental milestones perhaps secondary to growth hormone deficiency which has been reported (98% are short in stature).  Lifespan is short and many die in childhood.  Few live beyond the age of 40 years.

Alstrom syndrome has some similarities to Bardet-Biedl syndrome (209900) but differs in the absence of mental deficiency and polydactyly.

Genetics

This is an autosomal recessive disorder resulting from homozygous mutations in the ALMS1 gene on chromosome 2 (2p13).  The ALMS1 protein product is found in many cells throughout the body and is located in centrosomes and the base of cilia.  Its function is unknown.

More than 320 mutations have been reported. However, many cases remain in which no mutation has been found suggesting additional genetic heterogeneity remains.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for the basic disease.

References
Article Title: 

Alström Syndrome: Mutation Spectrum of ALMS1

Marshall JD, Muller J, Collin GB, Milan G, Kingsmore SF, Dinwiddie D, Farrow EG, Miller NA, Favaretto F, Maffei P, Dollfus H, Vettor R, Naggert JK. Alstrom Syndrome: Mutation Spectrum of ALMS1. Hum Mutat. 2015 Apr 2. doi: 10.1002/humu.22796. [Epub ahead of print].

PubMed ID: 
25846608

Alström syndrome

Marshall JD, Beck S, Maffei P, Naggert JK. Alstrom syndrome. Eur J Hum Genet. 2007 Dec;15(12):1193-202.

PubMed ID: 
17940554

Cole-Carpenter Syndrome 2

Clinical Characteristics
Ocular Features: 

Postnatally the eyes are prominent and hypertelorism has been reported.  The palpebral fissures slant downward and the root of the nose is angular. 

Systemic Features: 

This is primarily a skeletal disorder with impaired skull ossification and multiple bone fractures of prenatal origin.  It is sometimes confused with forms of osteogenesis imperfecta.  The skull is poorly ossified and frequent diaphyseal fractures of the long bones occur leading to motor delays and short stature.  Rib fractures are sometimes seen. Intelligence seems to be normal.  A receding chin has been noted and the hard palate is highly vaulted.  The midface is flat.

Genetics

This disorder results from compound heterozygous mutations in the SEC24D gene (4q26).  Only a few patients have been reported.

For a somewhat similar but autosomal dominant disorder see Cole-Carpenter Syndrome 1 (112240).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Physical activity should be restricted to noncontact sports and where the cranium has ossification defects a helmet should be worn.  Fractures should be appropriately treated.

References
Article Title: 

Mutations in SEC24D, Encoding a Component of the COPII Machinery, Cause a Syndromic Form of Osteogenesis Imperfecta

Garbes L, Kim K, Riess A, Hoyer-Kuhn H, Beleggia F, Bevot A, Kim MJ, Huh YH, Kweon HS, Savarirayan R, Amor D, Kakadia PM, Lindig T, Kagan KO, Becker J, Boyadjiev SA, Wollnik B, Semler O, Bohlander SK, Kim J, Netzer C. Mutations in SEC24D, Encoding a Component of the COPII Machinery, Cause a Syndromic Form of Osteogenesis Imperfecta. Am J Hum Genet. 2015 Mar 5;96(3):432-9.

PubMed ID: 
25683121

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