Increased Frequency of Autism by Previous Diagnosis and Screening in Children with Fetal-Neonatal Alloimmune Thrombocytopenia (FNAIT) with and without an Intracranial Hemorrhage (ICH).

BACKGROUND

Fetal-Neonatal AlloImmune Thrombocytopenia (FNAIT) results from parental platelet antigen incompatibility and maternal alloimmunization, most commonly to platelet antigen HPA-1a. De Vos et al. identified mild-moderate neurologic injury in 26% of 31 FNAIT-affected children aged 6-14 without past ICH. Suspicions from NAITbabies members, along with the De Vos observations, led to a survey evaluation of autism in FNAIT-affected children.

OBJECTIVE(S): This study explored the frequency of autism both by previous diagnosis and by screening in FNAIT-affected children with and without having had an ICH.

STUDY DESIGN

A de-identified survey was made available to mothers in NAITbabies, assessing risk of autism using four age-specific autism screening scales: Q-CHAT-10 for ages 18-24 months (n=18); M-CHAT-R 2-4 years(n=61); AQ-10-Child 4 -11 years (n=175); and AQ-10-Adolescent for >12 years (n=66). Mothers reported their child's ICH status and pre-screening autism diagnoses. Survey responses were scored using specific questionnaire algorithms.

RESULTS

Among 320 FNAIT-affected children, 24 (7.5%) had a previous autism diagnosis and 64 (20%) screened at risk. Among 182 children with known ICH status, that could be linked to an autism questionnaire response, 33 had suffered an ICH and 149 had not. Both pre-existing and screening autism diagnoses increased with age in both ICH and non-ICH groups, peaking in the 12+ age group: 67% with ICH and 36% without ICH. Autism findings were higher among ICH children but were most striking in the non-ICH group. 7.5% of the 4-11 age group (no ICH) and 18% of the 12+ age group (no ICH) already had been diagnosed with autism. With screening for high risk of autism, these numbers more than doubled to 19% (4-11 age group) and 36% (12+ age group). Positive predictive values of the latter two questionnaires were 0.94 and 0.86, respectively.

CONCLUSIONS

In FNAIT-affected children without an ICH, rates of autism were surprisingly high and became more apparent with age. These findings highlight the need for early screening and ongoing careful monitoring of children affected by FNAIT, even without known ICH, who can no longer be considered "consequence-free."