Miller-Dieker Syndrome with der(17)t(12;17)(q24.33;p13.3)pat Presenting with a Potential Risk of Mis-identification as a de novo Submicroscopic Deletion of 17p13.3 / 대한진단검사의학회지

Miller-Dieker syndrome involves a severe type of lissencephaly, which is caused by defects in the lissencephaly gene (LIS1). We report the case of a female infant with der(17)t(12;17)(q24.33;p13.3)pat caused by an unbalanced segregation of the parental balanced translocation of 17p with other chromosomes. The proband presented with facial dysmorphism, arthrogryposis, and intrauterine growth retardation. Most cases of Miller-Dieker syndrome have a de novo deletion involving 17p13.3. When Miller-Dieker syndrome is caused by an unbalanced translocation, mild-to-severe phenotypes occur according to the extension of the involved partner chromosome. However, a pure partial monosomy derived from a paternal balanced translocation is relatively rare. In this case, the submicroscopic cryptic deletion in the proband was initially elucidated by FISH, and karyotype analysis did not reveal additional chromosome abnormalities such as translocation. However, a family history of recurrent pregnancy abnormalities strongly suggested familial translocation. Sequential G-banding and FISH analysis of the father's chromosomes showed that the segment of 17p13.3-->pter was attached to the 12qter. Thus, we report a case that showed resemblance to the findings in cases of a nearly pure 17p deletion, derived from t(12;17), and delineated by whole genome array comparative genomic hybridization (CGH). If such cases are incorrectly diagnosed as Miller-Dieker syndrome caused by de novo 17p13.3 deletion, the resultant improper genetic counseling may make it difficult to exactly predict the potential risk of recurrent lissencephaly for successive pregnancies.

Comparing Two Diagnostic Laboratory Tests for Several Microdeletions Causing Mental Retardation Syndromes: Multiplex Ligation-Dependent Amplification vs Fluorescent In Situ Hybridization / 대한진단검사의학회지

BACKGROUND: Microdeletion syndromes not detectable by conventional cytogenetic analysis have been reported to occur in approximately 5% of patients with unexplained mental retardation (MR). Therefore, it is essential to ensure that patients with MR are screened for these microdeletion syndromes. Mental retardation syndrome multiplex ligation-dependent probe amplification (MRS-MLPA) is a new technique for measuring sequence dosages that allows for the detection of copy number changes of several microdeletion syndromes (1p36 deletion syndrome, Williams syndrome, Smith-Magenis syndrome, Miller-Dieker syndrome, DiGeorge syndrome, Prader-Willi/Angelman syndrome, Alagille syndrome, Saethre-Chotzen syndrome, and Sotos syndrome) to be processed simultaneously, thus significantly reducing the amount of laboratory work. METHODS: We assessed the performance of MLPA (MRC-Holland, The Netherlands) for the detection of microdeletion syndromes by comparing the results with those generated using FISH assays. MLPA analysis was carried out on 12 patients with microdeletion confirmed by FISH (three DiGeorge syndrome, four Williams syndrome, four Prader-Willi syndrome, and one Miller-Dieker syndrome). RESULTS: The results of MLPA analysis showed a complete concordance with FISH in 12 patients with microdeletion syndromes. CONCLUSIONS: On the basis of these results, we conclude that MLPA is an accurate, reliable, and cost-effective alternative to FISH in the screening for microdeletion syndromes.

A Case of Miller-Dieker Syndrome with Infantile Spasm and Lennox-Gastaut Syndrome / 대한소아신경학회지

Miller-Dieker syndrome is a contiguous gene deletion syndrome involving chromosome 17p13.3, which is characterized by type 1(classical) lissencephaly and typical craniofacial abnormalities. Children with Miller-Dieker syndrome have profound psychomotor retardation, seizures that often are intractable, chronic feeding problems that lead to recurrent pneumonia, and shortened lifespan. We have experienced a Miller-Dieker syndrome female who has lived to 8years, showing severe mental and motor retardation and intractable epilepsy. She was diagnosed as Miller-Dieker syndrome in the neonatal period, showing typical facial features, type 1 lissencephaly, and chromosome 17p13.3 microdeletion in fluorescence in situ hybridization. Infantile spasm occurred at 4 months of age and progressed to Lennox-Gastaut syndrome at 3 years and 6 months, both of which were not controlled by antiepileptic drugs.

Lissencephaly child showing FISH negative and mutation in DCX gene with normal parental genetic makeup.

Lissencephaly is a clinically and genetically heterogeneous malformation of the brain, leading to a severe disabling condition and seizures. The recent discovery of molecular techniques and identification of lissencephaly genes (LIS 1 and DCX) has allowed etiologic diagnosis of this disorder. We describe a patient with lissencephaly in whom fluorescence in situ hybridization and DCX mutation analysis determined etiologic diagnosis, allowing precise genetic counseling and providing prenatal diagnosis for the family.

A Case Report of Miller-Dieker Syndrome / 대한주산의학회잡지

Miller-Dieker Syndrome (MDS) is a contiguous gene deletion syndrome of chromosome 17p13.3, characterized by classical lissencephaly (lissencephaly type 1) and distinct facial features. Children with MDS present with severe developmental delay, epilepsy and feeding problems. The lissencephaly represents the severe end of the spectrum with generalized agyria, or agyria and some frontal pachy- gyria. Prenatal diagnosis is available and consists of fetal chromosomal analysis by karyotyping or fluorescence in situ hybridization (FISH), on chorion villus sampling or amniocentesis. Sonographic diagnosis in general cannot be accomplished earlier than late second trimester, when the characteristic cerebral anomalies can be noted. The progressive microcephaly and failure of development of both sulci and gyri are suggestive of lissencephaly. We report the case of a pregnant woman of 24 weeks gestation who presented with ventriculomegaly on antenatal sonography and hydrocephalus, and corpus callosum agenesis on fetal MRI, which was diagnosed as MDS by karyotyping and FISH on amniocentesis.

A Case of Miller-Dieker Syndrome without Characteristic Facial Anomaly / 대한진단검사의학회지

Miller-Dieker syndrome is a multiple malformation syndrome characterized by severe lissencephaly and characteristic facial abnormalities at birth. It is associated with visible or submicroscopic deletions within chromosome 17p13.3 including PAFAH1B1 (LIS1) gene. We report a six-month-old boy who presented with spasm and generalized myoclonic seizures. The patient was born at 40 weeks' gestation to a 36-year-old woman and showed developmental delay without microcephaly or prominent facial abnormality. Magnetic resonance imaging of the brain showed a few gyrus (lissencephaly). High resolution cytogenetic analysis from peripheral blood showed a normal karyotype. However, fluorescence in situ hybridization (FISH) of the metaphase chromosome using Miller-Dieker/ILS probe (Oncor, Gaithersburg, Maryland, USA) revealed only one signal of probe, indicating a microdeletion of 17pl3.3 region including PAFAH1B1 (LIS1) gene. We suggest that FISH 17p13.3 studies should be performed in addition to a standard metaphase analysis in patients with lissencephaly even if facial anomaly is not noted. A confirmatory diagnosis using FISH would be helpful in terms of leading to allow genetic counseling and availability prenatal diagnosis to the family.