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TCEAL1 loss-of-function results in an X-linked dominant neurodevelopmental syndrome and drives the neurological disease trait in Xq22.2 deletions. Am J Hum Genet 2022 Nov 07



Pubmed ID





An Xq22.2 region upstream of PLP1 has been proposed to underly a neurological disease trait when deleted in 46,XX females. Deletion mapping revealed that heterozygous deletions encompassing the smallest region of overlap (SRO) spanning six Xq22.2 genes (BEX3, RAB40A, TCEAL4, TCEAL3, TCEAL1, and MORF4L2) associate with an early-onset neurological disease trait (EONDT) consisting of hypotonia, intellectual disability, neurobehavioral abnormalities, and dysmorphic facial features. None of the genes within the SRO have been associated with monogenic disease in OMIM. Through local and international collaborations facilitated by GeneMatcher and Matchmaker Exchange, we have identified and herein report seven de novo variants involving TCEAL1 in seven unrelated families: three hemizygous truncating alleles; one hemizygous missense allele; one heterozygous TCEAL1 full gene deletion; one heterozygous contiguous deletion of TCEAL1, TCEAL3, and TCEAL4; and one heterozygous frameshift variant allele. Variants were identified through exome or genome sequencing with trio analysis or through chromosomal microarray. Comparison with previously reported Xq22 deletions encompassing TCEAL1 identified a more-defined syndrome consisting of hypotonia, abnormal gait, developmental delay/intellectual disability especially affecting expressive language, autistic-like behavior, and mildly dysmorphic facial features. Additional features include strabismus, refractive errors, variable nystagmus, gastroesophageal reflux, constipation, dysmotility, recurrent infections, seizures, and structural brain anomalies. An additional maternally inherited hemizygous missense allele of uncertain significance was identified in a male with hypertonia and spasticity without syndromic features. These data provide evidence that TCEAL1 loss of function causes a neurological rare disease trait involving significant neurological impairment with features overlapping the EONDT phenotype in females with the Xq22 deletion.

Author List

Hijazi H, Reis LM, Pehlivan D, Bernstein JA, Muriello M, Syverson E, Bonner D, Estiar MA, Gan-Or Z, Rouleau GA, Lyulcheva E, Greenhalgh L, Tessarech M, Colin E, Guichet A, Bonneau D, van Jaarsveld RH, Lachmeijer AMA, Ruaud L, Levy J, Tabet AC, Ploski R, Rydzanicz M, Kępczyński Ł, Połatyńska K, Li Y, Fatih JM, Marafi D, Rosenfeld JA, Coban-Akdemir Z, Bi W, Gibbs RA, Hobson GM, Hunter JV, Carvalho CMB, Posey JE, Semina EV, Lupski JR


Michael Muriello MD Assistant Professor in the Pediatrics department at Medical College of Wisconsin
Erin Syverson MGC Director, Assistant Professor in the Institute for Health and Equity department at Medical College of Wisconsin