A Case Series and Review of CDKL5 Deficiency Disorder: More than Rett

Juan Pablo Appendino,Cheryl R Greenberg,Aizeddin A Mhanni,Tyler Peikes,Jessica N Hartley

doi:10.31487/j.gg.2020.01.02

Abstract

CDKL5 Deficiency Disorder (CDD) or CDKL5-associated epileptic encephalopathy (CAEE) is a distinct X-linked dominant epileptic encephalopathy that shares many features with Rett syndrome. In the past decade, mutations in CDKL5 gene were identified as part of the molecular heterogeneity of MECP2- negative Rett syndrome. CDD has increasingly gained recognition as a distinct molecular and clinical phenotype. Here we present four new patients with CDD: one with a clinical presentation of reflex seizures previously reported as a case report by the same group, and three cases with novel disease-causing mutations. The emerging distinct phenotype of CDD should allow the clinician to suspect the diagnosis early and avoid a lengthy diagnostic odyssey.

Highlights

CDKL5-associated epileptic encephalopathy (CAEE) or CDKL5 Deficiency Disorder (CDD) has been increasingly recognized in the last decade as a distinct clinical entity [1, 2]
CDD has been historically characterized by seizures and Rett-like features that emerge in the first year of life and may even satisfy criteria for atypical Rett syndrome (RTT) [8]
We present a case series of four patients with CDD, one with the unusual presentation of reflex seizures and three with novel mutations not previously reported

Summary

Introduction

CDKL5-associated epileptic encephalopathy (CAEE) or CDKL5 Deficiency Disorder (CDD) has been increasingly recognized in the last decade as a distinct clinical entity [1, 2]. CDD or Early Infantile Epileptic Encephalopathy, Type 2 (OMIM # 300672) usually presents in early infancy with seizures, severe development delay, loss of milestones and postnatal microcephaly [3]. CAEE or CDD was originally described by several groups in 2004-2005 [4,5,6,7]. This was motivated in large part by the heterogeneity of the loose grouping of diseases referred to alternately as Rett syndrome (RTT), atypical Rett syndrome, variant Rett syndrome or Rett-like syndromes. Mutations in CDKL5, FOXG1, ANKRD31, STXBP1 and CHRNA5 have been identified in some MECP2-negative patients [8, 10, 11]

Results

Discussion

Conclusion