Group of diseases characterized by intellectual disability of variable severity linked to a mutation in chromosome X.  These mutations affect generally only one or a few families. They affect only the boys and the women who carry the mutation are asymptomatic or slighty affected except for the MRX99 form that involves also the women.

-        MRX2 [MIM 300 428] : mutation of the MRX2 gene (Xp22.3): macrocephaliy, squared face

-        MRX4 [MIM 314 580]: mutation of the ZC4H2 gene (Xq11.2) with arthrogryposis, hypotonia (see contractures of the feet-muscle atrophy- oculomotor apraxia syndrome) or Wieacker-Wolff syndrome

-        MRX14 [MIM 300 062] : Xq11.3-q13.3

-        MRX 15 and MRX 49, or Raynaud-Claes syndrome [MIM 300 114] : mutation of the CLCN4 gene (Xp22.2): in addition to the mental retardation, ataxia, convulsions, behavior disorders, facial dysmorphism

-        MRX17 and 31 [MIM 300 705] : microduplication including the HSD17B10 and HUWE1 genes

-        MRX18 and 78 : mutation of the IQSEC2 (Xp11.22)

-        MRX19 [MIM 300 844] : mutation of the RPS6KA3 gene (Xp22.12); other mutations of the same gene cause the Coffin-Lowry syndrome

-        MRX20 [MIM 300 047]: Xp11-q21

-        MRX23 [MIM 300 046]: Xq23-q24

-        MRX 29-32-33-38-43-52-54-76 and 87 [MIM 300 419]: mutation of the ARX gene (Xp21.3); variable phenotype: from lissencephaly type 2 to Proud [MIM 300 004], Parlington [MIM 309 510] and infantile spasms without cerebral malformation [MIM 308 350] syndromes

-        MRX34 [MIM 300 143]: mutation of the IL1RAPL1 gene (Xp21.3-p21.2); autistic traits

-        MRX41 [MIM 300 849]: mutation of the GDI1 gene (Xq28)

-        MRX42 [MIM 300 372]: Xq26

-        MRX44 [MIM 309 549]: mutation of the FTSJ1 gene (Xp11.23)

-        MRX45 [MIM 300 498]: Xp11.3-p11.21

-        MRX46 [MIM 300 436]: Xq25-q26

-        MRX47 [MIM 300 558]: mutation of the PAK gene (Xq23); short stature, sometimes psychiatric problems

-        MRX50 [MIM 300115]: mutation of the SYN1 gene (Xp11.3-p11.2)

-        MRX 53 [MIM 300 324]: Xq22.2-q26

-        MRX58 [MIM 300 210]: mutation of the TSPAN7 gene (Xp11.4)

-        MRX61 [MIM 300 978]: mutation of the RLIM gene (Xq13.2); Tonne-Kalscheuer syndrome, with a possible congenital diaphragmatic hernia (similar to Fryns syndrome)

-        MRX63 [MIM 300 387]: mutation of the ACLS4 gene (Xq23)

-        MRX72 [MIM 300 271]: mutation of the RAB39B gene (Xq28); intellectual disability sometimes associated with early Parkinson disease (Waisman syndrome)

-        MRX73 [MIM 300 355]: Xp22.2

-        MRX77 [MIM 300 454]: Xq12-q21.3

-        MRX81 [MIM 300 433]: Xp11.2-q12

-        MRX82 [MIM 300 518]: Xq24-q25

-        MRX84 [MIM 300 505]: Xp11.3-q22.3

-        MRX88 [MIM 300 852]: Xq24

-        MRX89 [MIM 300 848]: Xp11.3

-        MRX90 [MIM 300 850]: mutation of the DLG3 gene (Xq3.1)

-        MRX92 [MIM 300 851]: Xp11.3

-        MRX95 [MIM 300 716]: undetermined locus

-        MRX96 [MIM 300 802]: mutation of the SYP gene (Xp11.23)

-        MRX97 [MIM 300 803]: mutation of the ZNF711 gene (Xq21.1)

-        MRX99 [MIM 300 919]: mutation of the USP9X gene (Xp11.4). This mutation is also responsible in its heterozygous form, for the female-restricted X-linked facial dysmorphism-short stature-choanal atresia-intellectual  disability syndrome(see this term)

-        MRX101 [MIM 300 928]: mutation of the MIDZ gene (Xq22.3)

-        MRX104 [MIM 300 983]: mutation of the FRMPD4 gene (Xp22.2)

-        MRX105 [MIM 300 984]: mutation of the USP27X gene (Xp11.23)

-        MRX107 [MIM 301 013]: mutation of the CXorf56 gene (Xq24)

Anesthetic implications:

mental disability of variable severity

References : 

Updated: April 2022