Dudenhoeffer v. Secretary of Health and Human Services, 12-477

K.T., born August 2008, had a febrile seizure in April 2009; received MMR on August 6, 2009 and developed recurrent myoclonic‑astatic seizures beginning ~August 15–18, 2009.
She was treated with antiepileptics (Keppra, Zonisamide, Depakote); EEGs showed generalized epileptiform abnormalities; MRI was normal.
Treating neurologists diagnosed a myoclonic‑astatic epilepsy (Doose syndrome/MAE) with expressive language delay; records and experts disputed whether she also had epileptic encephalopathy (EE).
Petitioner alleged MMR caused K.T.’s MAE/EE via autoimmune mechanisms (molecular mimicry, bystander activation, epitope spreading), citing studies including Obregon et al. (Caspr2 peptide work) and older measles/MMR EEG/encephalopathy reports.
Respondent’s expert (Dr. Holmes) argued the April 2009 febrile seizure showed epilepsy onset pre‑MMR or otherwise that the cited evidence and mechanistic links were speculative and insufficient.
Special Master found K.T. does have EE but held Petitioner failed Althen prongs 1 and 2 (insufficient reliable medical theory and no logical sequence of cause‑effect); Petitioner met prong 3 (temporal proximity) but overall entitlement was denied.

Issue	Petitioner’s Argument	Respondent’s Argument	Held
Diagnosis: whether K.T. has EE in addition to MAE	K.T. plateaued in development after vaccination; plateau counts as EE	EE requires regression; K.T. did not regress and treating docs did not diagnose EE	Court found K.T. has EE (plateau qualifies as failure to develop)
Althen prong 1 (medical theory linking MMR to MAE)	MMR induced autoimmune response (molecular mimicry → anti‑Caspr2 or similar antibodies) causing MAE; bystander activation/epitope spread also possible	The cited studies are limited/indirect (small, artificial, different diseases); no reliable mechanism connecting MMR → Caspr2 antibodies → MAE	Theory rejected as insufficient and too many analytical gaps; prong 1 not met
Althen prong 2 (logical sequence of cause and effect)	Vaccine was the final environmental ‘‘hit’’ tipping a genetic predisposition into MAE; timing and clinical change after MMR support causation	April 2009 febrile seizure shows epilepsy onset pre‑MMR; treating doctors did not link MMR to later seizures	No persuasive logical causal sequence established; prong 2 not met
Althen prong 3 (temporal relationship)	Onset of characteristic seizures ~9 days after MMR; literature supports 5–14 day window for encephalopathy after MMR	Disputes onset and relevance of cited epidemiology; argues earlier seizure undermines timing	Petitioner met prong 3 (temporal proximity) but this alone is insufficient to prove causation

Althen v. Sec’y of HHS, 418 F.3d 1274 (Fed. Cir. 2005) (sets three‑prong framework for off‑Table Vaccine Act causation)
Moberly v. Sec’y of HHS, 592 F.3d 1315 (Fed. Cir. 2010) (vaccine must be a but‑for and substantial factor cause)
Pafford v. Sec’y of HHS, 451 F.3d 1352 (Fed. Cir. 2006) (Althen prong 1 requires more‑likely‑than‑not that vaccine can cause alleged injury)
Knudsen v. Sec’y of HHS, 35 F.3d 543 (Fed. Cir. 1994) (theory must be legally probable and supported by reliable medical explanation)
Cedillo v. Sec’y of HHS, 617 F.3d 1328 (Fed. Cir. 2010) (analytical gap doctrine; reject opinions with too great a gap between data and conclusion)
De Bazan v. Sec’y of HHS, 539 F.3d 1347 (Fed. Cir. 2008) (temporal relationship assessed against medical understanding of etiology)
Capizzano v. Sec’y of HHS, 440 F.3d 1317 (Fed. Cir. 2006) (petitioners may rely on circumstantial evidence and medical opinion for causation)
Joiner v. General Electric Co., 522 U.S. 136 (1997) (courts may exclude expert conclusions with an analytical gap)
Grant v. Sec’y of HHS, 956 F.2d 1144 (Fed. Cir. 1992) (temporal association alone is insufficient to prove causation)
Caves v. Sec’y of HHS, 100 Fed. Cl. 119 (2011) (special master may reject expert theory as too remote from evidence)