pervasive developmental disorder childhood disintegrative disorder https://github.com/monarch-initiative/mondo/issues/4537 https://rarediseases.info.nih.gov/diseases/6040/childhood-disintegrative-disorder https://www.malacards.org/card/childhood_disintegrative_disease heller syndrome dementia infantilis SCTID:61831009 GARD:0006040 UMLS:C0236791 NCIT:C97164 MedDRA:10008522 MONDO:0015681 SCTID:71961003 childhood disintegrative disease icd11.foundation:1460615954 Orphanet:168782 MEDGEN:472967 disintegrative psychosis DOID:13487 A rare pervasive developmental disorder with a disease onset before the age of three and characterized by a dramatic loss of behavioral and developmental functioning after atleast two years of normal development. Manifestations of the disease include loss of speech, incontinence, communication and social interaction problems, stereotypical autistic behaviors and dementia. ICD9:299.1