title: Autosomal recessive retinitis pigmentosa caused by mutations in the MAK gene.
abstract: OBJECTIVE
  To determine the disease expression in autosomal recessive (ar) retinitis pigmentosa (RP) caused by mutations in the MAK (male germ cell-associated kinase) gene.
  
  
  METHODS
  Patients with RP and MAK gene mutations (n = 24; age, 32-77 years at first visit) were studied by ocular examination, perimetry, and optical coherence tomography (OCT).
  
  
  RESULTS
  All but one MAK patient were homozygous for an identical truncating mutation in exon 9 and had Ashkenazi Jewish heritage. The carrier frequency of this mutation among 1207 unrelated Ashkenazi control subjects was 1 in 55, making it the most common cause of heritable retinal disease in this population and MAK-associated RP the sixth most common Mendelian disease overall in this group. Visual acuities could be normal into the eighth decade of life. Kinetic fields showed early loss in the superior-temporal quadrant. With more advanced disease, superior and midperipheral function was lost, but the nasal field remained. Only a central island was present at late stages. Pigmentary retinopathy was less prominent in the superior nasal quadrant. Rod-mediated vision was abnormal but detectable in the residual field; all patients had rod>cone dysfunction. Photoreceptor layer thickness was normal centrally but decreased with eccentricity. At the stages studied, there was no evidence of photoreceptor ciliary elongation.
  
  
  CONCLUSIONS
  The patterns of disease expression in the MAK form of arRP showed some resemblance to patterns described in autosomal dominant RP, especially the form caused by RP1 mutations. The similarity in phenotypes is of interest, considering that there is experimental evidence of interaction between Mak and RP1 in the photoreceptor cilium.
authors: Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA. edwin-stone@uiowa.edu
authors: Edwin M
authors: EM
authors: Stone
authors: Xunda
authors: X
authors: Luo
authors: Elise
authors: E
authors: Héon
authors: Byron L
authors: BL
authors: Lam
authors: Richard G
authors: RG
authors: Weleber
authors: Jennifer A
authors: JA
authors: Halder
authors: Louisa M
authors: LM
authors: Affatigato
authors: Jacqueline B
authors: JB
authors: Goldberg
authors: Alexander
authors: A
authors: Sumaroka
authors: Sharon B
authors: SB
authors: Schwartz
authors: Artur V
authors: AV
authors: Cideciyan
authors: Samuel G
authors: SG
authors: Jacobson
mesh_terms: D000328:Adult; D000368:Aged; D005091:Exons / Q000235:genetics; D005136:Eye Proteins / Q000235:genetics; D005808:Genes, Recessive; D006801:Humans; D008869:Microtubule-Associated Proteins; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D020419:Photoreceptor Cells, Vertebrate / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012174:Retinitis Pigmentosa / Q000235:genetics* / Q000503:physiopathology; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests
chemical_list: D005136:Eye Proteins; D008869:Microtubule-Associated Proteins; C120042:RP1 protein, human; D017346:Protein Serine-Threonine Kinases; C081931:MAK protein, human