cognitive delay

Perrault Syndrome

Clinical Characteristics
Ocular Features: 

Nystagmus and limited extraocular movements are usually present in PRLTS1.  Optic atrophy and poor visual acuity have been reported. Ptosis may be present.  The clinical manifestations are variable among and within the types.  Rod dysfunction and ‘retinal atrophy’ were reported in one patient.  The majority of patients have had only limited ocular evaluations.

Systemic Features: 

This is a sex-influenced condition in which both sexes have a sensorineural hearing deficit and neurodegenerative disease (both central and peripheral) but only the females have gonadal dysgenesis.  Motor development is often delayed and ataxia along with a peripheral sensory neuropathy and a variable degree of limb weakness can be present.  Learning difficulties, cognitive decline, and frank mental retardation are frequently described.  The cerebellum may be atrophic.

There is considerable variability in the clinical signs.

Genetics

The combination of hearing loss in males and females, ovarian dysgenesis in females, and variable neurologic signs including external ophthalmoplegia and sometimes optic atrophy is known as Perrault syndrome.  The ocular movement abnormalities are seen primarily in PRLTS1. 

At least 5 unique mutations have been found accounting for types PRLTS1-5.  PRLTS1 (233400) results from mutations in HSD17B4 (5q23.1), type PRLTS2 (614926) is caused by mutations in the HARS2 gene, PPRLTS3 (614129) by mutations in the CLPP gene, PRLTS4 (615300) by mutations in the LARS2 gene, and PRLTS5 (616138) by mutations in C10orf2 (listed in this database as External Ophthalmoplegia, C10orf2, and mtDNA mutations,.

The inheritance pattern among different types may be autosomal recessive or autosomal dominant.

Pedigree: 
Autosomal dominant
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment is known.

References
Article Title: 

Perrault syndrome: further evidence for genetic heterogeneity

Jenkinson EM, Clayton-Smith J, Mehta S, Bennett C, Reardon W, Green A, Pearce SH, De Michele G, Conway GS, Cilliers D, Moreton N, Davis JR, Trump D, Newman WG. Perrault syndrome: further evidence for genetic heterogeneity. J Neurol. 2012 May;259(5):974-6.

PubMed ID: 
22037954

Perrault syndrome in sisters

McCarthy DJ, Opitz JM. Perrault syndrome in sisters. Am J Med Genet. 1985 Nov;22(3):629-31.

PubMed ID: 
4061497

Temtamy Syndrome

Clinical Characteristics
Ocular Features: 

Bilateral chorioretinal colobomas may be present and involve the optic nerve in one-third of patients.  Visual acuity is not measureable but significant vision impairment is evident in most patients and may be progressive in some individuals.  Several have been reported with dislocated lenses, ptosis, microcornea, cataracts, microphthalmia, myopia, and posterior staphylomas.

Systemic Features: 

Mild, nonspecific craniofacial dysmorphism is often present.  Some form of macrocephaly, with an elongated face, low-set ears, and micrognathia has been reported.  Short stature is of the proportionate type.  Significant developmental delay is evident during childhood and patients are nonverbal. A variety of cardiovascular anomalies such as septal defects, aortic dilation, and patent ductus arteriosus have been described. MRI shows mild hypoplasia of the corpus callosum.   The gait may be ataxic and some (59%) individuals have spasticity of limb muscles with or without contractures.  Seizures develop in early childhood, usually before the age of 3 years, and are difficult to control. 

Genetics

The inconsistent and highly variable phenotype hints that this is a genetically heterogeneous condition.  Many patients seem to have an autosomal recessive condition secondary to mutations in C12orf57 (12p13.31).

A syndrome consisting primarily of colobomas, ptosis, hypertelorism, and global delay (243310) has some similar clinical features but is caused by mutations in ACTG1.

Treatment
Treatment Options: 

No therapy is available for the syndrome but attempts to control the seizures should be made. 

References
Article Title: 

Exome sequencing identifies compound heterozygous mutations in C12orf57 in two siblings with severe intellectual disability, hypoplasia of the corpus callosum, chorioretinal coloboma, and intractable seizures

Platzer K, Huning I, Obieglo C, Schwarzmayr T, Gabriel R, Strom TM, Gillessen-Kaesbach G, Kaiser FJ. Exome sequencing identifies compound heterozygous mutations in C12orf57 in two siblings with severe intellectual disability, hypoplasia of the corpus callosum, chorioretinal coloboma, and intractable seizures. Am J Med Genet A. 2014 May 5. [Epub ahead of print].

PubMed ID: 
24798461

Whole-exome sequencing identifies mutated c12orf57 in recessive corpus callosum hypoplasia

Akizu N, Shembesh NM, Ben-Omran T, Bastaki L, Al-Tawari A, Zaki MS, Koul R, Spencer E, Rosti RO, Scott E, Nickerson E, Gabriel S, da Gente G, Li J, Deardorff MA, Conlin LK, Horton MA, Zackai EH, Sherr EH, Gleeson JG. Whole-exome sequencing identifies mutated c12orf57 in recessive corpus callosum hypoplasia. Am J Hum Genet. 2013 Mar 7;92(3):392-400.

PubMed ID: 
23453666

New autosomal recessive multiple congenital abnormalities/mental retardation syndrome with craniofacial dysmorphism absent corpus callosum, iris colobomas and connective tissue dysplasia

Temtamy SA, Salam MA, Aboul-Ezz EH, Hussein HA, Helmy SA, Shalash BA. New autosomal recessive multiple congenital abnormalities/mental retardation syndrome with craniofacial dysmorphism absent corpus callosum, iris colobomas and connective tissue dysplasia. Clin Dysmorphol. 1996 Jul;5(3):231-40. Review.

PubMed ID: 
8818452
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