Homocystinuria

Answer is A (Homocystinuria) :

Homocystinuria is inherited as an autosomal recessive disorder.

Disorder                                    Inheritance

G-6 PD deficiency                  X-Linked

Myotonic dystrophy                Autosomal dominant

Otospongiosis                         Autosomal dominant

Ans. Homocystinuria

Bilateral subluxation of lens:
Marfan’s syndrome – upwards and outwards
Homocystinuria – downwards and inwards

Ans. is `b’ i.e., Homocystinuria

Bilateral subluxation of lens:

Marfan’s syndrome – upwards and outwards

Homocystinuria – downwards and inwards.

• Homocystinuria due to cystathionine-4-synthetase deficiency is an autosomal recessive disorder of methionine metabolism.
• Ocular complications in untreated patients include ectopia lentis, secondary glaucoma, optic atrophy, and retinal detachment. 
• There has been progressive lens dislocation in both eyes, bilateral and is frequently inferior.

Ans:B.)Homocystinuria

Bilateral subluxation of lens:

Marfan’s syndrome – upwards and outwards

Homocystinuria – downwards and inwards.

• Homocystinuria due to cystathionine-4-synthetase deficiency is an autosomal recessive disorder of methionine metabolism.
• Ocular complications in untreated patients include ectopia lentis, secondary glaucoma, optic atrophy, and retinal detachment. 
• There has been progressive lens dislocation in both eyes, bilateral and is frequently inferior.

Ans:B.)Homocystinuria

This condition is  inferior lens subluxations 

Uniocular diplopia together with finding of shining golden crescent on oblique and dark black crescent line on co­axial illumination (both b/o edge of subluxated lens) suggest a diagnosis of subluxated ectopia lentis.

Congenital rubella presents with deafness, cardiac malformation and cataract. 

Other defects include glaucoma, salt pepper retinopathy, microcephalus, cerebral palsy, intrauterine growth retardation, hepatosplenomegaly, mental & motor retardation. (but not ectopia lentis or lens dislocation)

Ans:B.)Homocystinuria.

The patient is suffering from inferior dislocation of lens.

Ectopia lentis

• It is a displacement or malposition of the eye’s crystalline lens from its normal location.
  • A partial dislocation of a lens is termed lens subluxation ; a complete dislocation of a lens is termed lens luxation .
• Pathophysiology
  • Disruption or dysfunction of the zonular fibers of the lens.
• Anterior lens luxation
  • With anterior lens luxation, the lens pushes into the iris or actually enters the anterior chamber of the eye. This can cause glaucoma, uveitis, or damage to the cornea. Anterior lens luxation is considered to be an ophthalmological emergency.
• Posterior lens luxation
  • With posterior lens luxation, the lens falls back into the vitreous humour and lies on the floor of the eye. This type causes fewer problems than anterior lens luxation, although glaucoma or ocular inflammation may occur.
• Common presenting symptoms (visual disturbance) include the following:
  • Red painful eye (secondary to trauma)
  • Decreased distance visual acuity (secondary to astigmatism or myopia)
  • Poor near vision (loss of accommodative power)
  • Monocular diplopia.
  • Retinal detachment is one of the most serious consequences of a dislocated lens.
• Cause:
  • Traumatic dislocation is the most common cause
  • Most common systemic conditions that are associated with ectopia lentis:
    • Marfan syndrome (bilateral,upward and outward)
      • Most frequent cause of heritable ectopia lentis. The syndrome is transmitted as an autosomal dominant trait
      • Features include tall stature, arachnodactyly, joint laxity, mitral valve prolapse, aortic dilatation, axial myopia, and increased incidence of retinal detachment.
    • Homocystinuria (bilateral,downward and inwards)
      • An inborn error of metabolism most often caused by a near absence of cystathionine b-synthetase (the enzyme that converts homocysteine to cystathionine).
      • Patients typically have fair skin with coarse hair, osteoporosis, mental retardation (nearly 50%), seizure disorder, marfanoid habitus, and poor circulation.
    • Weill–Marchesani syndrome(downwards)
      • Characterized by skeletal malformations (eg, short stature, brachycephaly, limited joint mobility, well-developed muscular appearance) and ocular abnormalities (eg, ectopia lentis, microspherophakia, lenticular myopia).
    • Sulfite oxidase deficiency
    • Hyperlysinemia