hypotonia

Microcephaly 20, Primary, Autosomal Recessive

Clinical Characteristics
Ocular Features: 

Microphthalmia and optic nerve hypoplasia with "blindness" seem to be common.

Systemic Features: 

Short stature and global developmental delay are usually present.  Poor or absent speech is characteristic and intellectual disability may be severe.  Few individuals can walk.  Foot deformities and hypotonia are often present.  Behavior problems are common having features of ADHD, autism, and aggression.  Foot deformities have been noted. 

Imaging of the brain may reveal cerebellar hypoplasia, a simplified gyral pattern, and absence of the corpus callosum. 

Genetics

Homozygous or compound heterozygous mutations in the KIF14 gene (1q32.1) are responsible for this disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Biallelic variants in KIF14 cause intellectual disability with microcephaly

Makrythanasis P, Maroofian R, Stray-Pedersen A, Musaev D, Zaki MS, Mahmoud IG, Selim L, Elbadawy A, Jhangiani SN, Coban Akdemir ZH, Gambin T, Sorte HS, Heiberg A, McEvoy-Venneri J, James KN, Stanley V, Belandres D, Guipponi M, Santoni FA, Ahangari N, Tara F, Doosti M, Iwaszkiewicz J, Zoete V, Backe PH, Hamamy H, Gleeson JG, Lupski JR, Karimiani EG, Antonarakis SE. Biallelic variants in KIF14 cause intellectual disability with microcephaly. Eur J Hum Genet. 2018 Mar;26(3):330-339.

PubMed ID: 
29343805

Mutations of KIF14 cause primary microcephaly by impairing cytokinesis

Moawia A, Shaheen R, Rasool S, Waseem SS, Ewida N, Budde B, Kawalia A, Motameny S, Khan K, Fatima A, Jameel M, Ullah F, Akram T, Ali Z, Abdullah U, Irshad S, Hohne W, Noegel AA, Al-Owain M, Hortnagel K, Stobe P, Baig SM, Nurnberg P, Alkuraya FS, Hahn A, Hussain MS. Mutations of KIF14 cause primary microcephaly by impairing cytokinesis. Ann Neurol. 2017 Oct;82(4):562-577.

PubMed ID: 
28892560

Schurrs-Hoeijmakers Syndrome

Clinical Characteristics
Ocular Features: 

Mild structural variants are common among the periocular structures.  There is marked hypertelorism in many individuals, the eyebrows are full and highly arched, the eyelashes are long, and the lid fissures slant downward.  Ptosis is often evident.  Myopia, nystagmus, and strabismus are frequently noted.  Colobomas have been reported.

Systemic Features: 

There is general psychomotor delay in development.  Intellectual disability (with IQs in the 50s) and hypotonia are common.  Speech is poor and sometimes absent.   Behavioral anomalies such as aggression and features of autism have been reported.  The anterior hairline is low, the mouth is wide with downturned corners, the nose is bulbous, the ears are large and low-set, and the teeth are often widely-spaced.  Cryptorchidism is common among males.

Renal and cardiac defects are common.  Brain MRIs often show cerebellar hypoplasia, enlarged ventricles, and nonspecific white matter changes.

Genetics

No treatment for the general disorder has been published.  Physical and speech therapy might be helpful

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment for the general disorder has been published.  Physical and speech therapy might be helpful.

References
Article Title: 

Clinical delineation of the PACS1-related syndrome--Report on 19 patients

Schuurs-Hoeijmakers JH, Landsverk ML, Foulds N, Kukolich MK, Gavrilova RH, Greville-Heygate S, Hanson-Kahn A, Bernstein JA, Glass J, Chitayat D, Burrow TA, Husami A, Collins K, Wusik K, van der Aa N, Kooy F, Brown KT, Gadzicki D, Kini U, Alvarez S, Fernandez-Jaen A, McGehee F, Selby K, Tarailo-Graovac M, Van Allen M, van Karnebeek CD, Stavropoulos DJ, Marshall CR, Merico D, Gregor A, Zweier C, Hopkin RJ, Chu YW, Chung BH, de Vries BB, Devriendt K, Hurles ME, Brunner HG; DDD study. Clinical delineation of the PACS1-related syndrome--Report on 19 patients. Am J Med Genet A. 2016 Mar;170(3):670-5.

PubMed ID: 
26842493

Mental Retardation, AD 53

Clinical Characteristics
Ocular Features: 

Dysmorphism of periocular structures includes downward slanting lid fissures, hypertelorism, and epicanthal folds.  Evidence for visual problems comes from visual tracking difficulties in some individuals.  Strabismus is present in a minority of patients.

Systemic Features: 

Delayed global development, cognitive impairment, and intellectual disability are major features of this form of mental retardation.  Hypotonia is present early.  Severe delays in onset of speech and walking are found in all patients and never develop in many individuals.  Behavior problems include, anxiety, hyperactivity, aggression, and autistic traits.  Feeding problems and breathing irregularities have been reported.  Seizures occur in some patients.

Brain MRIs are generally normal although corpus callosum anomalies are sometimes identified.

Genetics

Heterozygous mutations in the CAMK2A gene (5q32) have been found in individuals with this disorder.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment for the general condition has been reported.

References
Article Title: 

De Novo Mutations in Protein Kinase Genes CAMK2A and CAMK2B Cause Intellectual Disability

Kury S, van Woerden GM, Besnard T, Proietti Onori M, Latypova X, Towne MC, Cho MT, Prescott TE, Ploeg MA, Sanders S, Stessman HAF, Pujol A, Distel B, Robak LA, Bernstein JA, Denomme-Pichon AS, Lesca G, Sellars EA, Berg J, Carre W, Busk OL, van Bon BWM, Waugh JL, Deardorff M, Hoganson GE, Bosanko KB, Johnson DS, Dabir T, Holla OL, Sarkar A, Tveten K, de Bellescize J, Braathen GJ, Terhal PA, Grange DK, van Haeringen A, Lam C, Mirzaa G, Burton J, Bhoj EJ, Douglas J, Santani AB, Nesbitt AI, Helbig KL, Andrews MV, Begtrup A, Tang S, van Gassen KLI, Juusola J, Foss K, Enns GM, Moog U, Hinderhofer K, Paramasivam N, Lincoln S, Kusako BH, Lindenbaum P, Charpentier E, Nowak CB, Cherot E, Simonet T, Ruivenkamp CAL, Hahn S, Brownstein CA, Xia F, Schmitt S, Deb W, Bonneau D, Nizon M, Quinquis D, Chelly J, Rudolf G, Sanlaville D, Parent P, Gilbert-Dussardier B, Toutain A, Sutton VR, Thies J, Peart-Vissers LELM, Boisseau P, Vincent M, Grabrucker AM, Dubourg C; Undiagnosed Diseases Network, Tan WH, Verbeek NE, Granzow M, Santen GWE, Shendure J, Isidor B, Pasquier L, Redon R, Yang Y, State MW, Kleefstra T, Cogne B; GEM HUGO; Deciphering Developmental Disorders Study, Petrovski S, Retterer K, Eichler EE, Rosenfeld JA, Agrawal PB, Bezieau S, Odent S, Elgersma Y, Mercier S. De Novo Mutations in Protein Kinase Genes CAMK2A and CAMK2B Cause Intellectual Disability. Am J Hum Genet. 2017 Nov 2;101(5):768-788.

PubMed ID: 
29100089

Epileptic Encephalopathy, Early Infantile 58

Clinical Characteristics
Ocular Features: 

Infants are noted early to have poor fixation and visual following of targets.  Optic nerve hypoplasia is evident on brain MRIs.

Systemic Features: 

Epilepsy and development delay are hallmarks of this condition.  The seizures are of multiple types and have their onset in the first year of life.  The EEG often shows diffuse slowing, multifocal spikes and hypsarrhythmia.  These are often difficult to control.  Severe intellectual disability is usually present.  Feeding difficulties are evident early and slow growth is common.  Hypotonia is common but hyperreflexia and spasticity are also reported.

Brain MRIs show delayed or reduced myelination.  Acquired microcephaly is often seen.

Genetics

De novo heterozygous mutations in the NTRK2 gene (9p21.33) have been found in 4 unrelated individuals.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

High Rate of Recurrent De Novo Mutations in Developmental and Epileptic Encephalopathies

Hamdan FF, Myers CT, Cossette P, Lemay P, Spiegelman D, Laporte AD, Nassif C, Diallo O, Monlong J, Cadieux-Dion M, Dobrzeniecka S, Meloche C, Retterer K, Cho MT, Rosenfeld JA, Bi W, Massicotte C, Miguet M, Brunga L, Regan BM, Mo K, Tam C, Schneider A, Hollingsworth G; Deciphering Developmental Disorders Study, FitzPatrick DR, Donaldson A, Canham N, Blair E, Kerr B, Fry AE, Thomas RH, Shelagh J, Hurst JA, Brittain H, Blyth M, Lebel RR, Gerkes EH, Davis-Keppen L, Stein Q, Chung WK, Dorison SJ, Benke PJ, Fassi E, Corsten-Janssen N, Kamsteeg EJ, Mau-Them FT, Bruel AL, Verloes A, Ounap K, Wojcik MH, Albert DVF, Venkateswaran S, Ware T, Jones D, Liu YC, Mohammad SS, Bizargity P, Bacino CA, Leuzzi V, Martinelli S, Dallapiccola B, Tartaglia M, Blumkin L, Wierenga KJ, Purcarin G, O'Byrne JJ, Stockler S, Lehman A, Keren B, Nougues MC, Mignot C, Auvin S, Nava C, Hiatt SM, Bebin M, Shao Y, Scaglia F, Lalani SR, Frye RE, Jarjour IT, Jacques S, Boucher RM, Riou E, Srour M, Carmant L, Lortie A, Major P, Diadori P, Dubeau F, D'Anjou G, Bourque G, Berkovic SF, Sadleir LG, Campeau PM, Kibar Z, Lafreniere RG, Girard SL, Mercimek-Mahmutoglu S, Boelman C, Rouleau GA, Scheffer IE, Mefford HC, Andrade DM, Rossignol E, Minassian BA, Michaud JL. High Rate of Recurrent De Novo Mutations in Developmental and Epileptic Encephalopathies. Am J Hum Genet. 2017 Nov 2;101(5):664-685.

 

PubMed ID: 
291000083

Mental Retardation, AD 31

Clinical Characteristics
Ocular Features: 

A variety of ocular dysmorphisms have been described in this disorder including up-slanting lid fissures, epicanthal folds, hypertelorism, and telecanthus.  Ptosis was described in 1 patient.  Strabismus, nystagmus, and disconjugate gaze have been observed.  Visual acuity has not been reported but "variable visual impairment" has been described.  One patient was considered to have cortical visual impairment.

Systemic Features: 

Neonatal hypotonia and feeding difficulties are among the first signs along with seizure-like activity (50%) including infantile spasms.  EEG anomalies are present in the majority of individuals.  Gastroscopy tubes may be required in a significant minority of patients.  Hypotonic or myopathic facies is common.  Apneic episodes may be seen in the neonatal period and most infants have respiratory difficulties in the first year of life which may improve during this period.  Learning difficulties and features of autism are common.  Some patients are unable to walk while others have an ataxic or broad-based gait.  Speech may be absent or severely limited.  The forehead is prominent while the hard palate is usually highly vaulted.

Brain MRIs may show delayed myelination but such scans have been described as normal in other individuals.  Enlarged ventricles, a thin corpus callosum, and periventricular white matter changes may also be present.   Neuropathologic studies have revealed chronic inflammatory changes around the arterioles of deep while matter.

Genetics

Heterozygous mutations in the PURA gene (5q31) have been identified in this disorder.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Expanding the neurodevelopmental phenotype of PURA syndrome

Lee BH, Reijnders MRF, Abubakare O, Tuttle E, Lape B, Minks KQ, Stodgell C, Bennetto L, Kwon J, Fong CT, Gripp KW, Marsh ED, Smith WE, Huq AM, Coury SA, Tan WH, Solis O, Mehta RI, Leventer RJ, Baralle D, Hunt D, Paciorkowski AR. Expanding the neurodevelopmental phenotype of PURA syndrome. Am J Med Genet A. 2018 Jan;176(1):56-67.

PubMed ID: 
29150892

De novo mutations in PURA are associated with hypotonia and developmental delay

Tanaka AJ, Bai R, Cho MT, Anyane-Yeboa K, Ahimaz P, Wilson AL, Kendall F, Hay B, Moss T, Nardini M, Bauer M, Retterer K, Juusola J, Chung WK. De novo mutations in PURA are associated with hypotonia and developmental delay. Cold Spring Harb Mol Case Stud. 2015 Oct;1(1):a000356. doi: 10.1101/mcs.a000356.

PubMed ID: 
27148565

Mutations in PURA cause profound neonatal hypotonia, seizures, and encephalopathy in 5q31.3 microdeletion syndrome

Lalani SR, Zhang J, Schaaf CP, Brown CW, Magoulas P, Tsai AC, El-Gharbawy A, Wierenga KJ, Bartholomew D, Fong CT, Barbaro-Dieber T, Kukolich MK, Burrage LC, Austin E, Keller K, Pastore M, Fernandez F, Lotze T, Wilfong A, Purcarin G, Zhu W, Craigen WJ, McGuire M, Jain M, Cooney E, Azamian M, Bainbridge MN, Muzny DM, Boerwinkle E, Person RE, Niu Z, Eng CM, Lupski JR, Gibbs RA, Beaudet AL, Yang Y, Wang MC, Xia F. Mutations in PURA cause profound neonatal hypotonia, seizures, and encephalopathy in 5q31.3 microdeletion syndrome. Am J Hum Genet. 2014 Nov 6;95(5):579-83.

PubMed ID: 
25439098

Myopathy, Mitochondrial Anomalies, and Ataxia

Clinical Characteristics
Ocular Features: 

Ocular findings are variable.  One of three individuals with compound heterozygous mutations had a pigmentary retinopathy with pallor of the optic nerve but no visual abnormalities.  Her sister had only optic nerve pallor.  The eyes are described as "small" and "close-set".

No ocular findings were reported for the family with autosomal dominant inheritance.

Systemic Features: 

Ataxia, short stature, and gait difficulties from an early age are consistent findings.  Some patients are never able to walk.  Motor development is generally delayed.  Truncal and limb ataxia is a feature.  Some degree of intellectual disability is generally present and speech is often delayed.  

The face is long with a myopathic appearance.  Both micrognathia and a prominent jaw may be seen.  The palate is highly arched.  Patients are described as hypotonic and there is generalized muscle weakness both proximal and distal.  Distal sensory impairment has been described in the family with presumed dominant inheritance and there may be psychiatric symptoms of anxiety, depression, and schizophrenia.  Dysmetria with dysdiadochokinesis is often present and a fine intention tremor has been observed.

Mitochondria in fibroblasts exhibit abnormal dynamics and occur in a fragmented network.  Muscle biopsies reveal changes consistent with myopathy.  Serum creatine kinase may be elevated.

Genetics

Compound heterozygous mutations in the MSTO1 gene (1q22) have been found in two families with 3 affected individuals suggesting autosomal recessive inheritance.  In a third family, heterozygous mutations in the same gene were found in a mother and 3 of her adult children, consistent with autosomal dominant transmission.

Pedigree: 
Autosomal dominant
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Neurodevelopmental Disorder, Mitochondrial, with Abnormal Movements and Lactic Acidosis

Clinical Characteristics
Ocular Features: 

Optic atrophy is sometimes present.  Nystagmus, and strabismus are seen in some patients.  A pigmentary retinopathy was found in one individual.

Systemic Features: 

This is a clinically heterogeneous disorder with extensive neurological deficits.  Patients have feeding and swallowing difficulties from the neonatal period.  There is intrauterine growth retardation and postnatally patients usually exhibit psychomotor delays and intellectual disabilities.  Some develop seizures and few achieve normal developmental milestones.  Axial hypotonia is present from early infancy and most patients have muscle weakness and atrophy.  However, there may be spastic quadriplegia which is often associated with dysmetria, tremor, and athetosis.  Ataxia eventually develops in most patients. 

Brain imaging shows cerebral and cerebellar atrophy, enlarged ventricles, white matter defects, and delayed myelination. 

Incomplete metabolic studies suggest there may be abnormalities in mitochondrial oxidative phosphorylation activity in at least some tissues.  Most patients have an elevated serum lactate.

Death in childhood is common.

Genetics

Homozygous and compound heterozygous mutations in the WARS2 gene have been found in several families with this condition.  The considerable variation in the phenotype may at least partially be explained by the fact that an additional variant in the W13G gene is sometimes present which impairs normal localization of the WARS2 gene product within mitochondria.

The transmission pattern in several families is consistent with autosomal recessive inheritance.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported for the general condition.

References
Article Title: 

Biallelic variants in WARS2 encoding mitochondrial tryptophanyl-tRNA synthase in six individuals with mitochondrial encephalopathy

Wortmann SB, Timal S, Venselaar H, Wintjes LT, Kopajtich R, Feichtinger RG, Onnekink C, Muhlmeister M, Brandt U, Smeitink JA, Veltman JA, Sperl W, Lefeber D, Pruijn G, Stojanovic V, Freisinger P, V Spronsen F, Derks TG, Veenstra-Knol HE, Mayr JA, Rotig A, Tarnopolsky M, Prokisch H, Rodenburg RJ. Biallelic variants in WARS2 encoding mitochondrial tryptophanyl-tRNA synthase in six individuals with mitochondrial encephalopathy. Hum Mutat. 2017 Dec;38(12):1786-1795.

PubMed ID: 
28905505

Hypotonia, Infantile, with Psychomotor Retardation And Characteristic Facies 2

Clinical Characteristics
Ocular Features: 

Anomalies of periocular structures are part of the characteristic facial morphology.  The lid fissures slant downward and epicanthal folds are with ptosis are generally present.  Strabismus and nystagmus are characteristic features.

Systemic Features: 

This is a severe congenital neurodevelopmental disorder with global delay, hypotonia, and characteristic facies.  It is usually present at birth and soon manifest as a profound intellectual delay.  Most patients do not develop speech or independent motor skills.  Feeding difficulties are evident early and often require gastric tube placement for nutrition.  Failure to thrive is common.   Most patients have seizures of a tonic-clonic or atonic type which may be controlled with medication. 

Microcephaly, brachycephaly, plagiocephaly, and brachycephaly have been described.  A high forehead with frontal bossing, facial hypotonia, triangular facies have been described.  The ears are low-set and posteriorly rotated.  The upper lip is often thin and the mouth is commonly open.  The neck appears short, the nose is bulbous while the nasal bridge is prominent and the nares may be anteverted.

Brain imaging is normal in some patients but there is evidence of generalized cerebral atrophy, with a thin corpus callosum and decreased myelination in others.  Variable features include scoliosis, hip contractures, muscle wasting, and dyskinesias are sometimes seen.

Genetics

This disorder is caused by homozygous or compound heterozygous mutations in the UNC80 gene (2q34).  

For somewhat similar disorders see IHPRF1 (615419) and IHPRF3 (616900).

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Biallelic Mutations in UNC80 Cause Persistent Hypotonia, Encephalopathy, Growth Retardation, and Severe Intellectual Disability

Stray-Pedersen A, Cobben JM, Prescott TE, Lee S, Cang C, Aranda K, Ahmed S, Alders M, Gerstner T, Aslaksen K, Tetreault M, Qin W, Hartley T, Jhangiani SN, Muzny DM, Tarailo-Graovac M, van Karnebeek CD; Care4Rare Canada Consortium; Baylor-Hopkins Center for Mendelian Genomics, Lupski JR, Ren D, Yoon G. Biallelic Mutations in UNC80 Cause Persistent Hypotonia, Encephalopathy, Growth Retardation, and Severe Intellectual Disability. Am J Hum Genet. 2016 Jan 7;98(1):202-9.

PubMed ID: 
26708751

UNC80 mutation causes a syndrome of hypotonia, severe intellectual disability, dyskinesia and dysmorphism, similar to that caused by mutations in its interacting cation channel NALCN

Perez Y, Kadir R, Volodarsky M, Noyman I, Flusser H, Shorer Z, Gradstein L, Birnbaum RY, Birk OS. UNC80 mutation causes a syndrome of hypotonia, severe intellectual disability, dyskinesia and dysmorphism, similar to that caused by mutations in its interacting cation channel NALCN. J Med Genet. 2016 Jun;53(6):397-402.

PubMed ID: 
26545877

Al Kaissi Syndrome

Clinical Characteristics
Ocular Features: 

Reported facial dysmorphism features include periocular anomalies of ptosis, hypertelorism, down-slanting lid fissures, and epicanthal folds.  

Systemic Features: 

The phenotype is somewhat variable.  Intrauterine and postnatal growth retardation with hypotonia are common.   Moderate to severe intellectual disability is usually present and speech may be severely delayed.  The forehead is narrow, the nasal tip is broad, the nasal bridge is depressed, and the ears are low-set and posteriorly rotated.   Small hands and sometimes joint laxity are commonly present.  Cervical spine abnormalities including clefting, improper fusion, and segmentation anomalies are common.

Brain MRI may be normal but a small corpus callosum was present in some patients.

Genetics

Homozygous mutations in the CDK10 gene (16q24.3) are responsible for this disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

CDK10 Mutations in Humans and Mice Cause Severe Growth Retardation, Spine Malformations, and Developmental Delays

Windpassinger C, Piard J, Bonnard C, Alfadhel M, Lim S, Bisteau X, Blouin S, Ali NB, Ng AYJ, Lu H, Tohari S, Talib SZA, van Hul N, Caldez MJ, Van Maldergem L, Yigit G, Kayserili H, Youssef SA, Coppola V, de Bruin A, Tessarollo L, Choi H, Rupp V, Roetzer K, Roschger P, Klaushofer K, Altmuller J, Roy S, Venkatesh B, Ganger R, Grill F, Ben Chehida F, Wollnik B, Altunoglu U, Al Kaissi A, Reversade B, Kaldis P. CDK10 Mutations in Humans and Mice Cause Severe Growth Retardation, Spine Malformations, and Developmental Delays. Am J Hum Genet. 2017 Sep 7;101(3):391-403.

PubMed ID: 
28886341

Spastic Ataxia 8, Autosomal Recessive, with Hypomyelinating Leukodystrophy

Clinical Characteristics
Ocular Features: 

Reported ocular signs are limited to abnormal eye movements.  In other forms of spastic ataxia, nystagmus is evident in association with optic atrophy but no fundus examinations are reported in the 3 families with SPAX8.  Hypometric saccades and limited upgaze have also been found in these families.

Systemic Features: 

First signs and symptoms occur sometime in the first 5 years of life and often in the first year.   In 6 of 7 reported patients the presenting sign was nystagmus but one individual with reported onset of disease at age 5 years presented with ataxia.  Cerebellar signs, both truncal and limb, are usually present and the majority of individuals have evidence of dystonia.  Likewise, pyramidal signs are nearly always present.  Cerebellar dysarthria and titubation are often present with dystonic posturing and torticollis. 

Brain MRIs usually reveal cerebellar atrophy and widespread hypomyelination.  Two individuals in a single family had severe global psychomotor delays as well.  No sensory deficits were reported.  This disorder is progressive and patients in adulthood may require the use of a wheelchair.

Genetics

Homozygous mutations in the NKX6-2 (NKX6-2) gene (10q26.3) are responsible for this disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported for the general condition.

References
Article Title: 

Mutations in NKX6-2 Cause Progressive Spastic Ataxia and Hypomyelination

Chelban V, Patel N, Vandrovcova J, Zanetti MN, Lynch DS, Ryten M, Botia JA, Bello O, Tribollet E, Efthymiou S, Davagnanam I; SYNAPSE Study Group, Bashiri FA, Wood NW, Rothman JE, Alkuraya FS, Houlden H. Mutations in NKX6-2 Cause Progressive Spastic Ataxia and Hypomyelination. Am J Hum Genet. 2017 Jun 1;100(6):969-977.

PubMed ID: 
28575651

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