RESUMO
BACKGROUND: Silver-Russell syndrome (SRS) is one of the imprinting disorders characterized by prenatal and postnatal growth restriction, relative macrocephaly, body asymmetry and characteristic facial features. ~ 10% of SRS cases are known to be associated with maternal uniparental disomy of chromosome 7 (UPD(7)mat). Mosaic maternal segmental UPD of 7q (UPD(7q)mat) is very rare, had only been described in one case before. CASE PRESENTATION: We reported a second case of mosaic segmental UPD involving 7q. The patient presented with dysmorphic features including thin and short stature, triangular face, moderate protruding forehead, relative macrocephaly, fifth toe clinodactyly and irregular teeth, meeting the clinical diagnosed criteria of SRS. This case indicated that ~ 80% of mosaic UPD(7q)mat lead to the manifestation of main phenotypes of Silver-Russell syndrome. CONCLUSIONS: Our case support the notion that there are genes control postnatal growth on long arm of chromosome 7 and indicate that ~ 80% of UPD(7q)mat mosaicism level was contributed to the SRS phenotype.
RESUMO
De novo partial distal 1q trisomy is uncommon and mostly occurs in combination with monosomy of another chromosome due to a parental translocation. Distal 1q trisomy co-occurring with another de novo duplication on a separate chromosome is extremely rare. Here, we reported a patient carrying two large de novo interstitial duplications including a 20Mb duplication at 1q42-q44 and a 14.2Mb duplication at 9q21.12-q21.33. The patient presented with features of pre- and postnatal growth retardation, low birth weight, failure to thrive, developmental delay and frequent infection. Her dysmorphic features included macrocephaly, prominent forehead, triangular face, wide fontanelle, hypertelorism, flat nasal bridge, tented mouth, micrognathia, protruding and low-set ears, slender limbs with toe-walking appearance. In addition, she presented with subdural hematoma. The clinical presentations of this patient are mostly consistent with those of distal 1q trisomy syndrome or 9q interstitial duplication. The interstitial 1q trisomy may have contributed to the macrocephaly, prominent forehead and limb abnormalities of our patient. Either or both de novo duplications could have contributed to the features of growth retardation, developmental delay and dysmorphic features including hypertelorism, low-set ears and abnormal nose/nasal bridge.