Table 3.

Genetic Disorders with Choanal Atresia/Stenosis in the Differential Diagnosis of TXNL4A-Related Craniofacial Disorders

Gene(s)DiffDx DisorderMOIKey Features of DiffDx DisorderComment / Distinguishing Features
CHD7 CHARGE syndrome (See CHD7 Disorder.)ADIntraocular coloboma, heart defects, choanal atresia, growth deficiency, DD, genital hypoplasia, & ear anomaliesWhile some overlap exists between CHARGE syndrome & TXNL4A-related craniofacial disorders, esp choanal atresia, the CHARGE syndrome phenotype comprises clinical findings (intraocular coloboma, genital anomalies, & specific ear anomalies) not seen in TXNL4A-related craniofacial disorders. Note: The coloboma assoc w/TXNL4A-related craniofacial disorders involves the eyelid only & not intraocular structures.
EFTUD2 Mandibulofacial dysostosis with microcephaly (MFDM)ADMandibulofacial dysostosis (e.g., upslanting palpebral fissures, micrognathia, & ear anomalies), prenatal (usually progressive) microcephaly, & moderate-to-severe IDWhile some overlap exists between MFDM & TXNL4A-related craniofacial disorders, severe microcephaly & moderate ID in MFDM & distinctive facial phenotypes help to clinically distinguish the 2 disorders.
POLR1B
POLR1C
POLR1D
TCOF1 		Treacher Collins syndrome (TCS)AD
AR 1		Mandibulofacial dysostosis w/variable expressivity. Anomalies (usually restricted to craniofacial region) incl: downslanted palpebral fissures, hypoplasia of the zygomatic bones, lower-eyelid coloboma, microtia, & micrognathia.Downslanted palpebral fissures, hypoplasia of the zygomatic bones, & microtia have not been reported in TXNL4A-related craniofacial disorders. Cardiac defects & short stature are uncommon in TCS.

AD = autosomal dominant; AR = autosomal recessive; DD = developmental delay; DiffDx = differential diagnosis; ID = intellectual disability; MOI = mode of inheritance

1.

Autosomal dominant TCS is caused by a heterozygous pathogenic variant in TCOF1, POLR1D, or POLR1B; autosomal recessive TCS is caused by biallelic pathogenic variants in POLR1C or POLR1D.

From: TXNL4A-Related Craniofacial Disorders

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