What is the most likely genetic defect in a 3-year-old girl with a seizure disorder, strabismus, microcephaly, and developmental delay, taking valproic acid (valproate), presenting with a flattened occiput, prominent jaw, widely spaced teeth, hand flapping, stiff-legged gait, and limited communication skills?

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Differential Diagnosis

  • Single most likely diagnosis
    • B) Chromosome 15 deletion, maternally inherited: This condition is known as Prader-Willi syndrome when paternally inherited, but when maternally inherited, it's associated with Angelman syndrome. The symptoms described, such as seizure disorder, strabismus, happy demeanor, prominent jaw, widely spaced teeth, hand flapping, stiff-legged gait, short attention span, and lack of speech, are characteristic of Angelman syndrome.
  • Other Likely diagnoses
    • C) Chromosome 15 deletion, paternally inherited: Although this typically presents as Prader-Willi syndrome, which has a different set of characteristics (e.g., obesity, short stature, and hyperphagia), some symptoms can overlap, making it a consideration.
    • D) Mutation of MECP2 gene: This is associated with Rett syndrome, which primarily affects girls and can present with seizures, intellectual disability, and loss of speech. However, Rett syndrome typically includes hand wringing rather than flapping and often involves a period of regression.
  • Do Not Miss
    • None specifically stand out as "do not miss" in the traditional sense of being potentially deadly if missed, but recognizing the genetic basis of the condition is crucial for genetic counseling and management.
  • Rare diagnoses
    • A) Chromosome 7 deletion: This can be associated with Williams syndrome when it involves the deletion of the Williams syndrome critical region, but the symptoms don't closely match those described.
    • E) Trisomy 15: Mosaicism for trisomy 15 can lead to a condition with some overlapping features, but it's less likely given the specific constellation of symptoms.
    • F) Trisomy 21: Known as Down syndrome, this condition presents with distinct physical features (e.g., epicanthic folds, flat profile) and developmental delays, but the specific combination of symptoms described doesn't align closely with Down syndrome.

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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