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Zorluk: OrtaPediatric Genetic and Metabolic Disorders

Match each pediatric clinical presentation to the corresponding underlying enzyme deficiency.

  • A 3-year-old child presents with global developmental delay, hypopigmentation, and a distinct musty odor to their skin and urine.Phenylalanine hydroxylase
  • An 8-day-old infant develops progressive lethargy, poor feeding, alternating tone, and urine with a sweet, caramelized scent.Branched-chain alpha-ketoacid dehydrogenase
  • A 7-year-old patient is evaluated for tall stature, arachnodactyly, downward lens subluxation, and a history of early-onset thrombosis.Cystathionine beta-synthase
  • A 14-month-old toddler is asymptomatic, but the parents report that the child's urine develops a dark, brownish-black discoloration upon standing at room temperature.Homogentisate oxidase

Cevap

Vignette 1 corresponds to Phenylalanine hydroxylase (PKU). Vignette 2 corresponds to Branched-chain alpha-ketoacid dehydrogenase (MSUD). Vignette 3 corresponds to Cystathionine beta-synthase (Homocystinuria). Vignette 4 corresponds to Homogentisate oxidase (Alkaptonuria).
Each genetic disorder of amino acid metabolism produces a highly specific constellation of clinical findings based on the accumulated upstream metabolites and deficient downstream products, making a one-to-one mapping possible.

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1
Analyze Vignette 1 for classic metabolic toxidrome features.
Identified developmental delay, hypopigmentation, and musty odor.
These specific signs are pathognomonic for phenylketonuria, which is caused by phenylalanine hydroxylase deficiency.
2
Analyze Vignette 2 for classic metabolic toxidrome features.
Identified neonatal encephalopathy and sweet-smelling urine.
The caramelized odor combined with rapid neurological deterioration in the neonatal period indicates maple syrup urine disease (branched-chain alpha-ketoacid dehydrogenase deficiency).
3
Analyze Vignette 3 for classic metabolic toxidrome features.
Identified Marfanoid habitus, downward lens subluxation, and thrombosis.
The combination of Marfanoid features with a hypercoagulable state and inferior lens dislocation differentiates homocystinuria (cystathionine beta-synthase deficiency) from Marfan syndrome.
4
Analyze Vignette 4 for classic metabolic toxidrome features.
Identified asymptomatic presentation with urine turning black on standing.
This isolated chemical finding in an otherwise healthy child is the hallmark of alkaptonuria (homogentisate oxidase deficiency).

Anahtar Kavram

Amino acid metabolism disorders and their specific enzyme deficiencies
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Konular

Pediatric Genetic and Metabolic Disorders

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