Monocarboxylate transporter 8 is a specific thyroid hormone transporter found mutated in patients with severe psychomotor retardation and strangely abnormal thyroid hormone constellations.
A four-year-old boy with severe psychomotor retardation, facial appearance consistent with the fragile X syndrome, hypotonia, and overgrowth was found to have a deletion including the fragile X gene (FMR1).
By way of whole-exome sequencing, we identified a homozygous missense mutation in VARS2 in one subject with microcephaly and epilepsy associated with isolated deficiency of the mitochondrial respiratory chain (MRC) complex I and compound heterozygous mutations in TARS2 in two siblings presenting with axial hypotonia and severe psychomotor delay associated with multiple MRC defects.
By way of whole-exome sequencing, we identified a homozygous missense mutation in VARS2 in one subject with microcephaly and epilepsy associated with isolated deficiency of the mitochondrial respiratory chain (MRC) complex I and compound heterozygous mutations in TARS2 in two siblings presenting with axial hypotonia and severe psychomotor delay associated with multiple MRC defects.
Carbohydrate-deficient glycoprotein syndrome type 1 (CDG1) is an autosomal recessive, metabolic disorder with severe psychomotor retardation and a high mortality rate in early childhood.
Compound heterozygous variants in PGAP1 causing severe psychomotor retardation, brain atrophy, recurrent apneas and delayed myelination: a case report and literature review.
Congenital microcephaly, intractable seizures and severe psychomotor retardation characterize 3-phosphoglycerate dehydrogenase (3-PGDH) deficiency, a disorder of L-serine biosynthesis.
Haploinsufficiency of NTNG1, LPPR4, GPSM2, COL11A1 and VAV3 might have contributed to the severe psychomotor retardation and unusual craniofacial features in this patient.
Hemizygous MCT8 mutations in males cause severe psychomotor retardation, known as the Allan-Herndon-Dudley syndrome (AHDS), and abnormal serum TH levels.
In case 1, CMA revealed an approximately 140 kb deletion encompassing the first three exons of MEF2C in a 3-year-old patient with severe psychomotor retardation, periodic tremor, and an abnormal motor pattern with mirror movement of the upper limbs observed during infancy, hypotonia, abnormal EEG, epilepsy, absence of speech, autistic behavior, bruxism, and mild dysmorphic features.
Moreover, targeted sequencing of the SATB2 gene was performed in a 2-year-old girl with severe psychomotor retardation, facial hypotonia, and cleft palate who also exhibited some features of Rett syndrome.
Mutational analysis of the MCT8 gene revealed mutations or deletions in the MCT8 gene in unrelated male patients with severe psychomotor retardation and biochemical findings consistent with thyroid hormone resistance.
Mutations in MCT8 are associated with elevated serum T(3) levels and severe psychomotor retardation, indicating a pivotal role for MCT8 in brain development.
Mutations in MCT8 are associated with the Allan-Herndon-Dudley syndrome (AHDS), characterized by severe psychomotor retardation and altered serum thyroid parameters.
Mutations in MCT8 lead to Allan-Herndon-Dudley syndrome (AHDS), which is characterized by severe psychomotor retardation and abnormal thyroid hormone profile.