Table 1

 Summary of the different mutations found in the MECP2 gene in male patients

MutationPosRSDe novoAffected XY relativesAffected XX relativesMother XCICommentsRef
MBD, methyl binding domain; MR, relative presenting mental retardation; NA, not available; Pos, position with respect to known functional domains in the MECP2 protein; PPM-X, psychosis, pyramidal signs and macro-orchidism; RS, number of times this mutation was identified in a girl with Rett syndrome (according to the IRSA MECP2 variation database,, RTT, relative affected by RS; SNE, severe neonatal encephalopathy; TRD, transcription repression domain; XCI, X-chromosome inactivation.
Non-pathogenic variants are not listed.
Missense mutations
    R133CMBD92NoNoneRTT/MR85:15Mother has mild MRMasuyama et al10
    S134CMBD12NoNoneAtypical RTT98:2Budden et al11
    E137GMBD0NoMRNoneRandomUnclassified variantCouvert et al12
    A140VMBD0NoSevere MRMild MRRandomUnclassified variantOrrico et al13
MBD0NoSevere MRNoneRandomUnclassified variantCouvert et al12
MBD0NoPPM-XMild MRRandomUnclassified variantKlauck et al14
    F157IMBD0YesUnclassified variantKankirawatana et al15
    T158MMBD191NoSNERTT99:1Villard et al16
MBD191YesLynch et al17
    R167W0NoModerate MRNoneRandomUnclassified variantCouvert et al12
    P225LTRD0YesUnclassified variantMoog et al18
    P322S0NoNoneMRRandomMother has mild MRVentura et al19
Unclassified variant
    R344W0NANANANAUnclassified variantLaccone et al20
    P405L0NoNoneMRNAMother has mild MRMoog et al21
Unclassified variant
    K417M0NoNoneNoneRandomUnclassified variantKankirawatana et al15
    R453Q0NANANANAUnclassified variantCouvert et al12
In-Frame deletions
    P387del800NoMild MRNone100:0Yntema et al22
Frameshifts and nonsense mutations
    G163fs1NoRTTNAGeerdink et al23
    G252fsTRD3NoNoneRTTGermline mosaicismZeev et al24
    G269fsTRD9NoNoneRTTSkewedMother has mild MRWan et al7
TRD9YesLeuzzi et al25
TRD9YesKankirawatana et al15
    R270fsTRD3YesKankirawatana et al15
    G273fsTRD0YesRavn et al26
    L386fs7NoNoneNone95:5Dayer et al27
    Q406X0NoSevere MRNoneRandomMild MR in a carrier femaleMeloni et al28
    E472fs0YesKleefstra et al29
Large duplications
    430 kb0NoNoneNone90:10Duplication of AVPR2 to FLNAMeins et al30
    0.4–0.8 Mb0NoSevere MRNone>85:154 duplicationsVan Esch et al31
    0.4–0.8 Mb0NoSevere MRNone>90:106 duplicationsFriez et al32
    0.2–2.2 Mb0UNoneNoneSkewed6 duplications and 1triplicationDel Gaudio et al33
Abnormal karyotypes
    Y141X/XXYMBD6YesSchwartzman et al34
    T158M/XXYMBD191Yes76% of XXY cellsLeonard et al35
    E455X/XX1YesHeterozygous maleMaiwald et al36
Somatic mosaicism
    P56fs0YesClayton-Smith et al37
    R133HMBD3YesArmstrong et al38
    T158MMBD191Yes25% mutant cellsKleefstra et al39
    R270XTRD146Yes40% mutant cellsTopcu et al40