Analysis of two Chinese Han families with Duchenne/Becker muscular dystrophy / 上海交通大学学报（医学版）

Objective: To deepen the understanding of Duchenne/Becker muscular dystrophy by investigating dystrophin (DMD) gene variants in 2 Chinese Han families with this disease. Methods: Retrospective analysis of the clinical characteristics of the probands in two families with Duchnne/ Becker muscular dystrophy and the results of multiplex ligation-dependent probe amplification (MLPA) for the probands and their relatives was performed. Results: Three probands were identified by significantly-elevated creatine kinase levels. Two probands in family one are fraternal twin brothers with the same deletions of exons 8-9, while their mother has no abnormality at this site. The proband in family two is the little brother in a pair of fraternal twins with duplication of exons 48-51, and his mother has heterozygous duplication of exons 48-51. Conclusion: ① The presence of the same DMD gene mutation in the fraternal twins suggests that the mother may be a gonad chimera with this mutation if her gene detection of peripheral blood is normal. The mother must undergo prenatal gene diagnosis to reduce the risk of Duchenne/Becker muscular dystrophy in her offsprings. ② The exons 48-51 duplication of DMD gene is pathogenic mutation.

Simultaneous Streptococcus pneumoniae empyema in fraternal twins.

Streptococcus pneumoniae is the most common bacterial cause of community acquired pneumonia. The current trend in Streptococcus pneumoniae infections has been the rise of multi-drug resistance in the last two decades. We present the case of a pair of 16-month old African-American fraternal twins who presented to the emergency room on the same day for symptoms consistent with pneumonia. Upon further examination, the twins showed remarkably similar symptoms, and cultures revealed penicillin-resistant Streptococcus pneumoniae in both twins. The pneumonia affected both twins in the same way, but a tomography scan did not reveal any shared anatomical abnormalities to account for this near-identical progression. In a review of literature and case reports, there are no reported cases of fraternal twins with simultaneous or non-simultaneous pneumococcal pneumonia or effusions. This case suggests that there may be possible anatomical abnormalities in the fraternal twins which were not evident in routine testing that may have led to near-identical illnesses. The pathophysiology of the simultaneous and near identical infections is not clear but may reflect subtle genetic factors in the siblings.

Somatic and germ-line mosaicism of deletion 15q11.2-q13 in a mother of dyzigotic twins with Angelman syndrome.

Angelman syndrome (AS, OMIM105830) is a neurogenetic disorder caused by different genetic mechanisms. Determining the genetic mechanism is essential to establish the recurrence risk and the accuracy of genetic/reproductive counseling. The majority of AS patients present with a deletion of the 15q11.2-q13 region on the maternally derived chromosome. The other genetic mechanisms are: paternal disomy of chromosome 15, imprinting center defects, and mutations in the ubiquitin-protein ligase E3A gene (UBE3A). Different recurrence risks are associated with each specific genetic mechanism involved. We report on the study of dizygotic twins with classic phenotypic AS due to deletion of the same maternally derived chromosome 15. The mother presented with hypopigmented macular lesions on the inner side of both arms. Fibroblast culture studies of the maternal hypopigmented skin areas from both arms showed mosaicism for a normal cell line and for a second cell line with a 15q11.2-q13 deletion. This family represents the first demonstrated case of maternal somatic and germ line mosaicism for 15q11.2-q13 deletion as the cause of AS.

Neonatal tooth in fraternal twins: a case report.

Eruption of teeth at or immediately after birth is a relatively rare phenomenon. This condition has been the subject of curiosity and study since the time of beginning of beliefs and assumptions. The present case report accentuates the occurrence of neonatal teeth in twins; fraternal twins in particular which is rarest of its kind.