microcephaly

Intellectual Disability with Dysmorphic Facies and Ptosis

Clinical Characteristics
Ocular Features: 

The eyes appear widely spaced and the lid fissures slant downward.  Ptosis and blepharophimosis are present.  Strabismus is an uncommon feature.

Systemic Features: 

The characteristic facial profile (round, flat) is evident at birth. Microcephaly has been seen in some children.  Low birthweight is common.  Most infants feed poorly with general growth delay and short stature becoming evident in childhood.  Hypotonia and joint hypermobility are constant features.  Gross and fine motor movements appear uncoordinated.  Expressive language is delayed and impaired.  Intellectual disability is mild and achievement of developmental milestones may be delayed.  Seizures are seen in about half of affected individuals.  Brain MRIs may reveal mild white matter anomalies.  Spinal fusion among cervical vertebrae is common.

Individuals may live to adulthood.

Genetics

Heterozygous mutations in the BRPF1 gene (3p25) are responsible for this condition.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No effective treatment has been reported.

References
Article Title: 

Mutations in Histone Acetylase Modifier BRPF1 Cause an Autosomal-Dominant Form of Intellectual Disability with Associated Ptosis

Mattioli F, Schaefer E, Magee A, Mark P, Mancini GM, Dieterich K, Von Allmen G, Alders M, Coutton C, van Slegtenhorst M, Vieville G, Engelen M, Cobben JM, Juusola J, Pujol A, Mandel JL, Piton A. Mutations in Histone Acetylase Modifier BRPF1 Cause an Autosomal-Dominant Form of Intellectual Disability with Associated Ptosis. Am J Hum Genet. 2017 Jan 5;100(1):105-116.

PubMed ID: 
27939639

Mutations in the Chromatin Regulator Gene BRPF1 Cause Syndromic Intellectual Disability and Deficient Histone Acetylation

Yan K, Rousseau J, Littlejohn RO, Kiss C, Lehman A, Rosenfeld JA, Stumpel CT, Stegmann AP, Robak L, Scaglia F, Nguyen TT, Fu H, Ajeawung NF, Camurri MV, Li L, Gardham A, Panis B, Almannai M, Sacoto MJ, Baskin B, Ruivenkamp C, Xia F, Bi W; DDD Study.; CAUSES Study., Cho MT, Potjer TP, Santen GW, Parker MJ, Canham N, McKinnon M, Potocki L, MacKenzie JJ, Roeder ER, Campeau PM, Yang XJ. Mutations in the Chromatin Regulator Gene BRPF1 Cause Syndromic Intellectual Disability and Deficient Histone Acetylation. Am J Hum Genet. 2017 Jan 5;100(1):91-104.

PubMed ID: 
27939640

Optic Atrophy 11

Clinical Characteristics
Ocular Features: 

Optic atrophy is seen as early as 5 years of age but may be congenital in origin as hypoplasia of the optic nerve was present in all patients.  Three of 4 affected children also were myopic.

Systemic Features: 

This is a form of mitochondriopathy with considerable clinical heterogeneity.  A single consanguineous family with 4 affected children of ages 5-16 years of age has been reported.

Common features include short stature, microcephaly (1 had macrocephaly), hearing impairment. Ataxia, dysmetria, and athetotic movements may be present.  Motor and mental development are delayed as is expressive speech.  Intellectual disability is present in all 4 patients.  Leukoencephalopathy was seen in all patients and one had brain atrophy.  Cerebellar hypoplasia was present in 2 of four patients.

Muscle mitochondria in one patient had morphologic changes.  Lactate levels and lactate/pyruvate ratios were elevated in the blood and CSF fluid of three patients.

Genetics

Homozygous mutations in the YME1L1 gene (10p12.1) were responsible for this condition in 4 offspring of a consanguineous Saudi Arabian family.   This is a nuclear encoded mitochondrial gene.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.Hom

References
Article Title: 

Epileptic Encephalopathy, Early Infantile 47

Clinical Characteristics
Ocular Features: 

The fundus is normal early but optic atrophy with narrowed vessels develops eventually.  Cerebral visual impairment has been described.  VEPs were normal at 4 months of age in one patient.

Systemic Features: 

Tonic seizures have their onset in the first month of life.  These become refractory as documented by the EEG which shows severe background slowing, multifocal origins, and hypsarrhythmia.  Psychomotor development is severely delayed and accompanied by profound intellectual disability.  The two reported children were unable to stand and never developed speech.  Feeding difficulties requires tube feeding.  Microcephaly eventually develops along with axial hypotonia and limb ataxia.

Brain MRI was normal at 5 months of age in one individual but at 6 years old showed cerebellar atrophy.  Her younger male sibling at 2 months of age had a normal MRI but cerebellar atrophy was present at 3 years of age.  He died at 3.5 years while his older sib died at age 7 years.

Genetics

Heterozygous mutations in the FGF12 gene (3q28-q29) are responsible for this condition.  One family with 2 affected children has been reported but neither parent carried the mutation in somatic cells suggesting germline mosaicism.

For autosomal recessive forms of early onset epileptic encephalopathy in this database see Epileptic Encephalopathy, Early Infantile 28 (616211) and Epileptic Encephalopathy, Early Infantile 48 (617276).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment is available for the general condition.  Complete supportive care is required.  Seizures are described as 'refractory' to treatment.

References
Article Title: 

Cataracts, Congenital, Intellectual Disability, Abnormal Striatum, and ADHD

Clinical Characteristics
Ocular Features: 

Cataracts (not further described) were described as congenital although the diagnosis was usually made early in the first decade of life.  One patient was diagnosed at the age of 8 years with glaucoma and a cloudy cornea of the left eye.  Another patient had cataract surgery.  Visual acuities have not been reported.

Systemic Features: 

Four members of a consanguineous Saudi family have been reported with growth and mental retardation, microcephaly, dystonia, and spasticity.  IQs in the range of 77-89 were reported.  Linguistic delay is common.  Dysarthria and decreased cognitive function are present.  MRIs revealed thinning of the lentiform nucleus and swelling of the caudate heads.  

Genetics

Homozygous mutations in the KCNA4 (11p14.1) (176266) gene are responsible for this disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for the general condition.  Cataract surgery may be considered.

References
Article Title: 

KCNA4 deficiency leads to a syndrome of abnormal striatum, congenital cataract and intellectual disability

Kaya N, Alsagob M, D'Adamo MC, Al-Bakheet A, Hasan S, Muccioli M, Almutairi FB, Almass R, Aldosary M, Monies D, Mustafa OM, Alyounes B, Kenana R, Al-Zahrani J, Naim E, Binhumaid FS, Qari A, Almutairi F, Meyer B, Plageman TF, Pessia M, Colak D, Al-Owain M. KCNA4 deficiency leads to a syndrome of abnormal striatum, congenital cataract and intellectual disability. J Med Genet. 2016 Aug 31. pii: jmedgenet-2015-103637. doi: 10.1136/jmedgenet-2015-103637. [Epub ahead of print].

PubMed ID: 
27582084

Encephalopathy Due To Defective Mitochondrial And Peroxisomal Fission 2

Clinical Characteristics
Ocular Features: 

Visual impairment and optic atrophy are usually present.  Visual-evoked potentials may be negative or slowed severely.  Some degree of ophthalmoparesis is often present while frank external ophthalmoplegia can develop in the second year of life.  In one patient aged 7 years, MRI showed increased T2 signals in the optic radiation.

Systemic Features: 

Microcephaly becomes evident in the first year of life and seizures can appear in this period as well.  General developmental delays are present.  There may be evidence of Leigh-like basal ganglia disease.  Dysphagia may require the placement of a gastroscopy tube.  Truncal hypotonia can be so severe that sitting and head control are not possible.  However, there is often spasticity and hyperreflexia in the limbs.  EEG recordings show hypsarrhythmia.

Brain MRI may show increased T2 signaling in the global pallidus, thalamus, and the subthalamic nucleus.

Patients may never be able to sit or walk and usually do not develop speech.  

Genetics

Homozygous or compound heterozygous truncating mutations in the MFF gene (mitochondrial fission factor) (2q36.3) is responsible for this condition.  Patients with EMPF2 may have abnormally elongated and tubular mitochondria and peroxisomes in fibroblasts.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for the general disorder.  Gastrostomy tubes may be required to maintain adequate nutrition.  Airway hygiene is important.  Respiratory complications can be a factor in the early demise of children.

References
Article Title: 

Mitochondrial DNA Depletion Syndrome 3

Clinical Characteristics
Ocular Features: 

Nystagmus, disconjugate eye movements, and "optic dysplasia" have been noted.

Systemic Features: 

Infants feed poorly which is frequently associated with vomiting, failure to thrive, and growth delay.  They are hypothermic, hypoglycemic, and often jaundiced with signs of liver failure noted between birth and 6 months of age and death by approximately 1 year of age.  Hepatosplenomegaly is present early with abnormal liver enzymes, cholestasis, steatosis, and hepatocellular loss followed by cirrhosis with portal hypertension.  Metabolic acidosis, hyperbilirubinemia, hypoalbuminemia, and hypoglycemia are often present.  Mitochondrial DNA depletion in the liver approaches 84-90%.

All patients have encephalopathic signs with evidence of cerebral atrophy, microcephaly, hypotonia.  Hyperreflexia may be present and some infants have seizures.  Muscle tissue, however, has normal histology and respiratory chain activity.

Genetics

This disorder results from homozygous or compound heterozygous mutations in the DGUOK gene (2p13).

The same gene is mutated in PEOB4 (617070).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no effective treatment.  Liver transplantation in one infant was unsuccessful.  

References
Article Title: 

Rubinstein-Taybi Syndrome 2

Clinical Characteristics
Ocular Features: 

Highly-arched and bushy eyebrows are often seen.  The lashes are long and bushy and lid fissures tend to slope downward.

The ocular phenotype has not been fully described no doubt due to the rarity of cases.  Individuals with type 1 (RSTS1) have been described with congenital glaucoma, nystagmus, corneal abnormalities of shape (such as keratoglobus, sclerocornea, megalocornea), pigmentary retinopathy, and VEP evidence of rod and cone dysfunction have been described.

Systemic Features: 

The phenotype of RSTS2 is more variable than the somewhat similar RSTS1.  Less than 10% of individuals with Rubinstein-Taybi syndrome have type 2 while over 50% have type 1.  The facial dysmorphism nay be less severe in RSTS2.

Mild to moderate intellectual disability with psychosocial problems such as autism is nearly universal.  Microcephaly, a broad nasal bridge, a beaked nose, high-arched palate and some degree of micrognathia are characteristic.  The lower lip often appears 'pouty' and protrudes beyond the upper lip while the hard palate is highly arched.  Pregnancy may be complicated by pre-eclampsia and growth restriction.  Swallowing and feeding issues are common.  Syndactyly is often present and there is considerable variability in the size of the toes and thumbs.  Some patients with RSTS2 do not have evidence of the classic broad thumbs and toes characteristic of RSTS1.

Genetics

Heterozygous mutations in EP300 (22q13.2) have been found in this condition.  Virtually all cases occur de novo.  Rubinstein-Taybi Syndrome 1 (180849) is a phenotypically similar disorder resulting from a different mutation (CREBBP).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no treatment for this condition.

References
Article Title: 

Cerebral Palsy, Spastic Quadriplegic, 3

Clinical Characteristics
Ocular Features: 

One family with 4 affected sibs has been reported but without detailed information on ophthalmological findings.  Strabismus reported as exotropia in one individual, and "convergent retraction nystagmus" in another was present.  Supranuclear gaze palsy was described in one individual. 

Systemic Features: 

Borderline microcephaly has been reported.  Evidence for global neurologic disease, primarily spasticity, may be present as early as 3 months of age.  Intellectual disability ranges from borderline to severe.  Progression is somewhat variable but by the second decade there may be sufficient spastic quadriparesis and cognitive impairment that full time assistive care is required.  Dysarthria and dysphagia are also features and gastrostomy feeding tubes may be required to maintain nutrition.  Seizures are uncommon.

The MRI does not show major structural abnormalities and an EEG in one patient revealed only bifrontal spike-waves.

Genetics

This condition is caused by homozygous mutations in the ADD3 gene (10q24).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is known.

References
Article Title: 

Mutations in gamma adducin are associated with inherited cerebral palsy

Kruer MC, Jepperson T, Dutta S, Steiner RD, Cottenie E, Sanford L, Merkens M, Russman BS, Blasco PA, Fan G, Pollock J, Green S, Woltjer RL, Mooney C, Kretzschmar D, Paisan-Ruiz C, Houlden H. Mutations in gamma adducin are associated with inherited cerebral palsy. Ann Neurol. 2013 Dec;74(6):805-14.

PubMed ID: 
23836506

Heart and Brain Malformation Syndrome

Clinical Characteristics
Ocular Features: 

Microphthalmia is the cardinal ocular malformation.  Hypertelorism has been described.  Poor vision without further description has also been reported.   

Systemic Features: 

The ears are low-set, malformed, and posteriorly rotated.  The forehead is prominent and there is usually a wide anterior fontanel.  The nasal bridge is wide and frequently depressed while the lower lip is full and may be everted and split.  The palate is highly arched.  Physical growth is slow.  A ventricular septal defect is often present while the valves are hypoplastic and the aortic arch can be interrupted.

Microcephaly is often present and there may a profound delay in psychomotor development with truncal hypotonia and hyperreflexia in the limbs.   Brain imaging shows generalized atrophy with decreased myelination.  Cerebellar vermis hypoplasia has been reported.  Two of 5 patients were reported to have Dandy-Walker malformations, and a thin corpus callosum.  Seizures may occur.

Genetics

Homozygous mutations in the SMG9 gene (19q13.31) are responsible for this condition so far reported in 5 individuals in two unrelated consanguineous Arab families.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Mutations in SMG9, Encoding an Essential Component of Nonsense-Mediated Decay Machinery, Cause a Multiple Congenital Anomaly Syndrome in Humans and Mice

Shaheen R, Anazi S, Ben-Omran T, Seidahmed MZ, Caddle LB, Palmer K, Ali R, Alshidi T, Hagos S, Goodwin L, Hashem M, Wakil SM, Abouelhoda M, Colak D, Murray SA, Alkuraya FS. Mutations in SMG9, Encoding an Essential Component of Nonsense-Mediated Decay Machinery, Cause a Multiple Congenital Anomaly Syndrome in Humans and Mice. Am J Hum Genet. 2016 Apr 7;98(4):643-52.

PubMed ID: 
27018474

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: 

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