Concordancia entre una función de crecimiento del perímetro cefálico y la discapacidad intelectual en relación con la etiología de la microcefalia / Concordance between a head circumference growth function and intellectual disability in relation with the cause of microcephaly

INTRODUCCIÓN: Nuestro objetivo fue investigar la correlación entre patrones de crecimiento cefálico y discapacidad intelectual entre distintas presentaciones etiológicas de microcefalia. PACIENTES Y MÉTODOS: Se revisaron 3.269 gráficas de perímetro cefálico (PC) de una unidad de neuropediatría terciaria, seleccionándose 136 participantes con microcefalia. Utilizando las puntuaciones Z de las medidas de PC registradas definimos las variables: PC mínimo, caída de PC y recuperación de PC. Los pacientes se clasificaron según la existencia o no de discapacidad intelectual (CI inferior a 71) y la causa de la microcefalia (idiopática, familiar, sindrómica, sintomática y mixta). RESULTADOS: El uso del análisis discriminante permitió definir una función C como C=PC mínimo + caída de PC con un nivel de corte de puntuación Z de C=-4,32. En nuestra muestra, el 95% de los pacientes con resultados por debajo de este nivel, microcefalia severa, presentaban discapacidad intelectual. La concordancia global entre la función de PC y la presencia de discapacidad intelectual fue del 66%. En el grupo de sintomáticas y mixtas, esta concordancia alcanzó el 82%, en contraste con solo el 54% del grupo de idiopáticas y sindrómicas (p = 0,0002). CONCLUSIONES: La utilización de una función de crecimiento del PC discrimina la discapacidad intelectual en pacientes con microcefalia mejor que mediciones aisladas de PC, especialmente en etiologías secundarias y mixtas

INTRODUCTION: Our aim was to investigate the correlations between patterns of head growth and intellectual disability among distinct ætiological presentations of microcephaly. PATIENTS AND METHODS: 3,269 head circumference (HC) charts of patients from a tertiary neuropædiatric unit were reviewed and 136 microcephalic participants selected. Using the Z-scores of registered HC measurements we defined the variables: HC Minimum, HC Drop and HC Catch-up. We classified patients according to the presence or absence of intellectual disability (IQ below 71) and according to the cause of microcephaly (idiopathic, familial, syndromic, symptomatic and mixed). RESULTS: Using Discriminant Analysis a C-function was defined as C=HC Minimum + HC Drop with a cut-off level of C=-4.32 Z-score. In our sample 95% of patients scoring below this level, severe microcephaly, were classified in the disabled group while the overall concordance was 66%. In the symptomatic-mixed group the concordance between HC function and outcome reached 82% in contrast to only 54% in the idiopathic-syndromic group (P-value=0.0002). CONCLUSIONS: We defined a HC growth function which discriminates intellecutal disability of microcephalic patients better than isolated HC measurements, especially for those with secondary and mixed ætiologies

[Concordance between a head circumference growth function and intellectual disability in relation with the cause of microcephaly]. / Concordancia entre una función de crecimiento del perímetro cefálico y la discapacidad intelectual en relación con la etiología de la microcefalia.

INTRODUCTION: Our aim was to investigate the correlations between patterns of head growth and intellectual disability among distinct aetiological presentations of microcephaly. PATIENTS AND METHODS: 3,269 head circumference (HC) charts of patients from a tertiary neuropediatric unit were reviewed and 136 microcephalic participants selected. Using the Z-scores of registered HC measurements we defined the variables: HC Minimum, HC Drop and HC Catch-up. We classified patients according to the presence or absence of intellectual disability (IQ below 71) and according to the cause of microcephaly (idiopathic, familial, syndromic, symptomatic and mixed). RESULTS: Using Discriminant Analysis a C-function was defined as C=HC Minimum + HC Drop with a cut-off level of C=-4.32 Z-score. In our sample 95% of patients scoring below this level, severe microcephaly, were classified in the disabled group while the overall concordance was 66%. In the symptomatic-mixed group the concordance between HC function and outcome reached 82% in contrast to only 54% in the idiopathic-syndromic group (P-value=0.0002). CONCLUSIONS: We defined a HC growth function which discriminates intellectual disability of microcephalic patients better than isolated HC measurements, especially for those with secondary and mixed aetiologies.