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July 24, 2014 1:54 am / Leave a comment

NORD Information Services

      National Organization for Rare Disorders, IncHow many patients are treated at your hospital (Ruby Memorial) for Homocystinuria.

 

  • How many patients are treated at your hospital (Ruby Memorial) for Homocystinuria?   5
  • What is the plan for treatment?   Medications, and limit protein in their diets.
  • What degree are patients intellectually challenged? All 5 are intellectually challenged.
  • What is the life expectancy? Unknown the oldest is 40 according to Kim.
  • This disease was first detected in medical literature in 1962
  • It is a autosomal recessive genetic disorder
  • It is closely related to Marfan syndrome
  • It is potentially life threatening
  • Kenneth parents were told at age 7 months, that 70% of his brain had been damaged.
  • Parents who carry the gene have a 25% chance with each pregnancy that they will have a child with Homocystinuria
  • Risks that a normal child will be a carrier is 50%
  • There is only a 25% chance that their child will not be a carrier.
  • It affects males and females equally
  • World wide one in every 344,000 have the disease, the total number in the United states is unknown
  • Ruby treats 5 to 7 patients, the oldest is 40 years old.
  • Hyomocystinurisa is a rare metabolic condition
  • Caused by a reduced enzyme know as cystathionine betasyntase (CBS)
  • Enzymes are proteins that accelerates the rate of chemical reactions in the body.
  • Cystathione betasyntase deficiency is essential for growth and developmental
  • Skeletal abnormalities become noticeable during childhood
  • There are thinning and lengthening of the bones that cause great pain
  • Knees are bent inward so they touch when the legs are straightened. A highly arched foot causing an abnormal side ways curvature
  • Abnormally protruding chest or sunken chest.
  • Increased risk for blood clots which can cause strokes.
  • Affects organs of the body are the eyes, skeletal, central nervous system, and vascular system.
  • Detached retina, and blindness
  • Developmental delays
  • As puberty nears the limbs grow out of proportion to the trunk, anterior chest wall deformities may occur. The facial appearance may be alerted by prominence and protrusion of upper teeth due to overcrowding. One of the distinguishing features of classical homocystinuria, patients is the presence of osteoporosis especially spinal osteoporosis.
  • Another well known symptom of homocystinuria is thromboembolism, affecting both large and small arteries,and veins it is also the most striking cause of serious complications and mortality in the disease.
  • Mental Retardation is the most frequent central Nervous system abnormality and is often th first recognizable sign of homocystnuria. Thes patients show a wide variation in their IQ levels with a median IQ if 64, Episodic depression behavioral disorders, OCD, Schizophrenia, are some of the most common mental disorders appearing in these patients
  • Access have screened over 2,00,00 newborns, the current accumulation detection rate of homocystinuria is in 3,44,000. However this figure is considered by many as an underestimation of the true rate of occurrence. This is maninly due to the fact that in pyridoxine responsive cases, the most readily treatable from is preferentially missed by newborn screening mehods. The true rate of incidence is considered by many to be as high as 1 in 45,000. Based on the mutation rate formula
  • Homocysteine produced in the third step of the pathway is either regenerated into methionine or converted to cystahionine by combining serine and homocysteine
  • The reanaction is catalysed by the enzyme cystathionine-Bsynthase (CBS)
  • The deficiency of CBS due to inherited defects causes homocystinuria
  • Due to the absence of CBS enzyme, homocystien accumulates inn the blood serum leading to an increased excretion of homocystine in the urine.
  • Newborns are tested for homocystniisnuria before they leave the hospital. The test usually looks for high levels of MET. If the test is positive, blood or urine test can be done to confirm the diagnosis. These tests can detect high levels of MET. Homocysttinuria, and other sulphur-containing amino acids. Tests to detect an enzyme deficiency (such as cystathionine synthetase) can be done as well.
  • If a child is not tested at birth, a doctor may later discover the disorder based on symptoms. At that point, the following may be done.
  • Blood test to confirm the diagnosis
  • X ray to look for bone problems
  • An eye exam to look for eye problems
  • No specific cure has been discovered for homocystinuria; however, many people are treated using high doses of Vitamin B. Pyridoxine. Slightly less than 50% respond to this treatment and need to intake supplemental vitamin B6 for the rest of their lives. Those who do not respond require a low methionine diet, and most will need treatment with trimethlglcyine. A normal dose of folic acid supplement and occasionally adding cysteine to the diet.
  • Betaine (nnn-trimethlglcine) is used to reduce concentrations of homocystiene by promoting the conversion of homocysteine back to methionine the re-formed methionine is then gradually removed by in portion into body protein. The methioine that is not converted into protein is converted to S-adenosyl-methionine which goes on to form homocysteine again.
  • Betaine is, therefore, only effective if the quantity of methionine to be removed is small. Hence treatment includes both betainoe and a diet low in methionine. In classical homocystinuria the plasma methionine usually increases above the normal range of 30 micromoles/L and the concentrations should be monitored as potentially toxic level may be reached.
  • Genetic counseling is recommended for prospective parents with a family history of homocystinuria.
  • Prenatal diagnosis of homocystiuria is available and is made by culturing amniotic cells or chorionic villi to test for the presence or absence of cystathiornie synthase
  • If the diagnosis is made while a patient is young, a low methiorine diet started promptly and strictly adhered to can spare some mental retardation and other complications of the disease. For this reason some states screen for homocystinuria in all all newborns.
  • Kenneth is now 6, he is unable to form words, no sentences,.
  • He is able to point to items he may want.
  • He is not potty trained
  • He attends a special school, through FMRS
  • He is not blind
  • Goals for this project is where to direct families for support
  • To establish a support group in our area

References

 

 

 

What resources are available for the families and clients?