This case was reported by a lawyer and described the occurrence of neurological injury in a male subject who was vaccinated with hepatitis B vaccine (Engerix B) and or unidentified hepatitis B for prophylaxis.  On an unspecified date the subject received unspecified dose of hepatitis B vaccine.  According to the legal complaint, at an unspecified time after vaccination with hepatitis B vaccine, the subject experienced "serious and permanent neurological injuries" which were attributed to " toxic mercury exposure".  The following information was received via medical records.  The subject was vaccinated with diphtheria and tetanus toxoids and acellular pertussis vaccine (Dtpa, manufacturer unspecified) on 18 July 1991, 26 September 1991, and 16 January 1992.  The subject was also vaccinated with Haemophilus influenzae type B vaccine (Hib), live attenuated oral poliomyelitis vaccine (Polio vaccine), measles, mumps and rubella vaccine and strain not specified (MMR vaccine) for prophylaxis.  The subject's medical history included spastic diplegia and tremors on the date of initial Dtpa vaccination.  Family history included language delays.  On 29 August 1991, the subject experienced possible worsening of clonus and developmentally seemed on target.  At 12 months of age the subject was saying single words; however at 18 months old he went through " a major change" with a decrease in language, which became unintelligible.  He was examined in July 1993 due to concerns that he was not talking, although he had spoken words in the past.  In December 1993, the subject was diagnosed with pervasive development delay and moderate mental retardation.  ON 03 April 1995, examination revealed profound delays in receptive and expressive language, and profound delays in phonology.  In April 1998, the subject's problem list included autism/pervasive developmental disorder, and attention deficit disorder, and chronic medications included RITALIN.  A trial of clonidine resulted in worsening behavior problems including increased hyperactivity and aggressive behavior.  Comprehensive evaluations performed in November 1998 and December 1998 showed severe delays in the development of receptive and expressive language, atypical language, play and behavior development, severe preservation, and high levels of activity and distractibility.  Stanford-Binet Intelligence scale showed a composite score of 49 (mentally retarded range).  Additional problems included qualitative impairments in social interaction, communication, and maladaptive behaviors.  He was noted to be experiencing deterioration in his school at that time.  In February 2001, primary concerns included noncompliance, aggression, difficulty with transitions, and tantrums.  He exhibited toe walking.  In September 2001, additional concerns included elopement and elopement attempts, destructiveness, self stimulation (body rocking and hand flapping), separation anxiety, enuresis and encopresis, poor daily living skills and social withdrawal. Treatment included occupational and speech therapy.  In September 2002, Concerta was prescribed.  On 24 September 2003, it was determined that the subject and his family were able to communicate effectively and were not benefiting from therapy sessions; speech therapy was terminated. This case was assessed to be medially significant. (OMIC)