Article

Identification of KIF21A mutations as a rare cause of congenital fibrosis of the extraocular muscles type 3 (CFEOM3).

Department of Genetics, Children's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA.
Investigative Ophthalmology &amp Visual Science (Impact Factor: 3.66). 07/2004; 45(7):2218-23.
Source: PubMed

ABSTRACT Three congenital fibrosis of the extraocular muscles phenotypes (CFEOM1-3) have been identified. Each represents a specific form of paralytic strabismus characterized by congenital restrictive ophthalmoplegia, often with accompanying ptosis. It has been demonstrated that CFEOM1 results from mutations in KIF21A and CFEOM2 from mutations in PHOX2A. This study was conducted to determine the incidence of KIF21A and PHOX2A mutations among individuals with the third CFEOM phenotype, CFEOM3.
All pedigrees and sporadic individuals with CFEOM3 in the authors' database were identified, whether the pedigrees were linked or consistent with linkage to the FEOM1, FEOM2, and/or FEOM3 loci was determined, and the appropriate pedigrees and the sporadic individuals were screened for mutations in KIF21A and PHOX2A.
Twelve CFEOM3 pedigrees and 10 CFEOM3 sporadic individuals were identified in the database. The structures of eight of the pedigrees permitted the generation of meaningful linkage data. KIF21A was screened in 17 probands, and mutations were identified in two CFEOM3 pedigrees. One pedigree harbored a novel mutation (2841G-->A, M947I) and one harbored the most common and recurrent of the CFEOM1 mutations identified previously (2860C-->T, R954W). None of CFEOM3 pedigrees or sporadic individuals harbored mutations in PHOX2A.
The results demonstrate that KIF21A mutations are a rare cause of CFEOM3 and that KIF21A mutations can be nonpenetrant. Although KIF21A is the first gene to be associated with CFEOM3, the results imply that mutations in the unidentified FEOM3 gene are the more common cause of this phenotype.

0 Bookmarks
 · 
99 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Congenital cranial dysinnervation disorders (CCDDs) are phenotypes of congenital incomitant strabismus and/or ptosis related to orbital dysinnervation. CCDDs have been associated with dominant or recessive monogenic mutations in at least 7 different genes (CHN1, SALL4, HOXA1, KIF21A, PHOX2A, TUBB3, ROBO3) that cause phenotypes such as Duane retraction syndrome, congenital fibrosis of the extraocular muscles, and horizontal gaze palsy with progressive scoliosis. Recently, arthrogryposis with or without strabismus has been shown to be caused by recessive mutations in ECEL1, a gene likely involved in neuromuscular junction formation. The strabismus phenotype in ECEL1-related cases has not always been detailed but may be a form of CCDD. To better define the ECEL1-related ophthalmic phenotype, we detail ophthalmic findings in 4 affected siblings from a consanguineous family and review documented ophthalmic findings for other reported mutation-positive cases.
    Journal of American Association for Pediatric Ophthalmology and Strabismus 08/2014; 18(4):362-367. · 1.14 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To describe the phenotypic characteristics and clinical course of a sporadic case of congenital fibrosis of the extraocular muscles (CFEOM) and Möbius syndrome with a de novo mutation in the KIF21A gene encoding a kinesin motor protein. An individual with the rare combination of CFEOM and Möbius syndrome underwent comprehensive ophthalmologic and neurological evaluations. Magnetic resonance imaging (MRI) including diffusion tensor imaging (DTI) tractigraphy at 3T field strength was used to evaluate orbital, encephalic, and intracranial nerve integrity. The proband and her healthy parents underwent screening for mutations in the KIF21A, PHOX2A, and TUBB3 genes. The patient exhibited congenital, nonprogressive, bilateral external ophthalmoplegia, bilateral ptosis, bilateral facial palsy, and developmental delay. Her inability to blink resulted in severe exposure keratopathy and subsequent corneal perforation requiring a penetrating keratoplasty. MRI revealed an unremarkable configuration of the axial central nervous system and preservation of the intracranial portion of cranial nerves I, II, III, V, VI, VII, and VIII (cranial nerve IV is not normally visualized by MRI). A novel and de novo heterozygous KIF21A mutation (c.1056C>G, p.Asp352Glu) in a highly conserved region of the gene was present in the proband. The reported KIF21A D352E mutation and associated phenotype further expand the clinical and mutational spectrum of CFEOM and Möbius syndrome.
    Molecular vision 01/2014; 20:368-75. · 2.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Background: Duane retraction syndrome (DRS) is the most common of the congenital cranial dysinnervation disorders (CCDDs). CCDDs can be monogenic or chromosomal in origin. Identification of the genetic cause(s) in patients and families with DRS facilitates definitive diagnosis and provides insights into these developmental errors. Materials and Methods: This study described a young girl with DRS on the left and several additional developmental abnormalities. Clinical examination including neuroimaging, sequencing of candidate genes associated with DRS, and array comparative genomic hybridization (array CGH) were performed. Results: The proband had unilateral DRS type 3 on the left with somewhat low-set ears, mild motor delay with normal intelligence, and an asymmetric neck without a palpable right sternocleidomastoid muscle. Spine X-rays revealed a Klippel-Feil syndrome (KFS) and an MRI showed a webbed neck. She also had spina bifida at C8-T1 and a submucosal cleft palate. The parents of the proband were related with no other family member affected similarly. Sequencing of SALL4, CHN1, HOXA1, and TUBB3 did not show any mutation. Array CGH revealed de novo deletions of 21 Kb on chromosome 12q24.31 and 11 Kb on chromosome 22q13.31, each encompassing only one gene, ring finger protein 34, E3 ubiquitin protein ligase (RNF34) and peroxisome proliferator-activated receptor alpha (PPARA) respectively. Conclusions: This patient presents an unusual phenotype associated with a unique combination of two chromosomal microdeletions.
    Ophthalmic Genetics 05/2014; · 1.23 Impact Factor

Full-text (2 Sources)

Download
27 Downloads
Available from
May 16, 2014