Akademik Veri Yönetim Sistemi
EuroDysmorpho 2023, Lisbon, Portekiz, 13 - 16 Eylül 2023, ss.89-90
Introduc�on: Intellectual developmental disorder-70 (MRT70, OMIM#618402), a very rare phenotype with
an unknown prevalance, is caused by biallelic loss-of-func�on variants of RSRC1. RSRC1 gene encodes a
Serine and arginine-rich(SR)-related protein, localized to the nuclear speckled domain. SR proteins are
evolu�onarily conserved co-regulators of cons�tu�ve and alterna�ve pre-mRNA splicing. RSRC1 plays a
relevant role in the second step of pre-mRNA splicing. Furthermore, it may par�cipate in post-splicing mRNA
processing and func�on as a transcrip�onal regulator.
Case report: Here, we report a 17-year-old female pa�ent referred to our outpa�ent clinics for intellectual
disability and dysmorphism. Her parents were 1st degree cousins. She was born at the 38th week of gesta�on
with a birth weight of 2600 gr. She had a febrile seizure at 4 months old and has recurrent epilep�c seizures
since then. Her neuromotor development was delayed. She could sit unsupported at 2 years old, and walk
independently at 4 years old. She could talk with few words around 3 years of age. She had physical therapy
for 6 years. She had special educa�on but never learned to read/write. She generally had a friendly nature
but occasionally had tantrums. Her cranial MRI was normal. In her physical examina�on; her height, weight
and head circumference were normal. She had mild hypotelorism, straight eyebrows, a short filtrum, small
hands and feet, and bilateral flexion contractures at the elbows. Karyotype analysis was normal and at
microarray analysis, there was no likely pathogenic/pathogenic variants detected. Whole-exome sequencing revealed homozygous likely pathogenic RSRC1(NM_001271838.2):c.109C>T variant at the pa�ent and the
segrega�on analysis done by Sanger sequencing showed the healthy parents as carriers.
Conclusion: MRT70 is primarily characterized by variable degrees of intellectual disability. Developmental
delay, mild facial dysmorphism, febrile seizures, and behavioral abnormali�es have been reported in some
pa�ents. To our knowledge, approximately 25 pa�ents have been reported in the literature and dis�nc�ve
neurological features or facial dysmorphism have not been defined so far. We believe that the presented case
(pa�ent we report) will expand our understanding of this rare phenotype, and novel findings such as small
hands and feet, and flexion contractures of the elbows will occur as emerging syndromic clinical phenotype.