Clinical and molecular findings in eight Egyptian patients with suspected mitochondrial disorders and optic atrophy

Mitochondrial respiratory chain disorders [RCD] are a group of genetically and clinically heterogeneous diseases, caused due to defects of the respiratory chain. This study aimed to investigate the presence of common mtDNA point mutations in tRNALeu [UUR], tRNALys, MT-ATPase 6, MT-ND4, MT-ND1, MT-ND6 genes in eight Egyptian patients suspected to have mtDNA disease and optic atrophy. PCR-RFLP analysis was done for the detection of 3243A > G, 327IT > C, 8344A > G, and 8993T > G/C mtDNA point mutations. DNA direct sequencing was pursued for the detection of 11778G > A, 3460G > A and 14484T > C mtDNA point mutations. No point mutation of 3243A > G, 327IT > C, 8344A > G, and 8993T > G/C was detected in our group of patients. Four mtDNA polymorphisms in MT-ND1 and MT-ND4 genes [11467A > G, 11719G > A, 3348A > G and 3357G > A] were detected in three patients. Mitochondrial disorders are caused by a variety of genetic and racial factors, which differ among populations. The negative results of this study indicate that the chosen mutations might not be specific in Egyptians. Another explanation might be due to the low heteroplasmic levels of the mtDNA mutation. A registry for the different mtDNA mutations in Egyptian patients is highly recommended

Developmental abnormalities of mid and hindbrain: a study of 23 Egyptian patients

With the advent of neuroimaging modalities specifically, magnetic resonance imaging [MRI], recognition of developmental defects of posterior fossa has greatly improved. Is to delineate the clinical, cytogenetics and radiological features of patients with midhindbrain anomalies. Twenty-three patients with mid-hind brain malformations were included in this study. Complete clinical evaluation, cytogenetic analysis and neuroradiological study were done for each patient. Patients' sex ratio was [M: F/ 0.9:1] and the mean age was 2.17 years. Parental consanguinity was 86.9% and positive family history was recorded in 7 families. Based on clinico-radiological findings, patients were categorized as Joubert syndrome and related cerebellar disorders [34.8%], pontocerebellar hypoplasia [26.1%], lissencephaly cerebellar hypoplasia [13%], isolated cobblestone lissencephaly with normal muscle and eye [8.7%], isolated vermian hypoplasia [13%] and retrocerebellar cyst [4.4%]. Cytogenetic analysis revealed abnormalities in 3 patients [13%]; pericentric inversion of chromosome 8 in a patient with lissencephaly cerebellar hypoplasia, del 5p14.3-pter delineating Cri du chat syndrome and associated with vermian hypoplasia and del 18q21.1-qter in a patient with retrocerebellar cyst due to paternal balanced translocation t [4;18]. FISH for specific locus and whole chromosomal painting were used to document the assigned aberrations. Although most of the cerebellar malformations are of Mendelian inheritance, this study emphasizes the importance of chromosomal analysis for patients with posterior fossa anomalies. With more researches describing clinico-radiological characterization of hind brain dysgenesis will allow better understanding of these disorders, further delineation of relevant syndromes and new genes identification

Maternal balanced translocation [4;21] leading to an offspring with partial duplication of 4q and 21 q without phenotypic manifestations of down syndrome

We describe an 8-year old female with supernumerary chromosome der[21]t[4;21][q25;q22] resulting in partial trisomy 4q25-qter and partial trisomy 21[pter-q22]. The extra material was originated from a reciprocal balanced translocation carrier mother [4q;21q]. Karyotyping was confirmed by FISH using whole chromosome painting probes for 4 and 21q and using 21q22.13-q22.2 specific probe to rule out trisomy of Down syndrome critical region. Phenotypic and cytogenetic findings were compared with previously published cases of partial trisomy 4q and 21 q. Our patient had the major criteria of distal trisomy 4q namely severe psychomotor retardation, growth retardation, microcephaly, hearing impairment, specific facies [broad nasal root, hypertelorism, ptosis, narrow palpebral fissures, long eye lashes, long philtrum, carp like mouth and malformed ears] and thumbs and minor feet anomalies. In spite of detection of most of the 3 copies of chromosome 21, specific features of Down syndrome [DS] were lacked in this patient, except for notable bilateral symmetrical calcification of basal ganglia. This report represents further delineation of the phenotype-genotype correlation of trisomy 4q syndrome. It also supports that DS phenotype is closely linked to 21q22. Nevertheless, presence of basal ganglia calcification in this patient may point out to a more proximal region contributing in its development in DS, or that genes outside the critical region may influence or control manifestations of DS features

C677T polymorphism of the 5,10-Methylenetetra-hydrofolate reductase [MTHFR] gene as a risk factor for neural tube defects among Egyptian families

Methylenetetrahydrofolate reductase [MTHFR] deficiency leads to impairment in folate metabolism and is implicated as a risk factor for neural tube defects [NTDs]. C677T MTHFR polymorphism is associated with NTDs, in some populations. Although the prevalence of this mutation has been reported from various ethnic populations, no data concerning Egyptian are available. C677T polymorphism was analyzed by PCR-RFLP. The frequencies of the C677T MTHFR polymorphism was determined in 35 case mothers, 19 case fathers and 9 children with NTDs compared with healthy 30 matched controls. In addition, allele and genotype frequencies were classified into different groups according to offspring NTD phenotype, consanguinity of the parents and number of affected offspring with NTD and or abortion. The prevalence of the polymorphic, homozygous [T/T] and heterozygous [C/T] C677T MTHFR genotypes were 6.3% and 38.1%, respectively, giving an allele frequency of 0.25. We observed increased frequency of heterozygotes of MTHFR in NTDs mothers versus the control although, C677T allele frequency was 0.28 in controls. Consanguinity rate was 45.7% among our families but it seems unlikely that it had an additional effect on the heterozygosity of the mutant genotype in this sample. In conclusion, neither homozygosity nor heterozygosity for the C677T polymorphism in the MTHFR gene constitute a genetic risk factor in the total NTDs but could be a risk of spina bifida aperta in this sample of Egyptian families. It is noteworthy to mention that this is the first report from Egypt evaluating the relationship between MTHFR677C>T and NTD

Hallervorden-Spatz syndrome Variable imaging findings

Authors describe clinical features, CT scan and MRI findings of 4 Egyptian boys [3 brothers from one sibship and a sporadic case] with Hallervorden-Spatz syndrome [HSS]. These patients presented around the age of 10-years-old with rigidity, dystonia, dysarthria, mental deterioration with loss of previously acquired skills and choreoathetotic movements. The 3 brothers developed seizures around the age of 16 and the older brother died at the age of 20. Although, the CT scan of the 3 brothers showed bilateral symmetrical calcification of the basal ganglia, the MRI of the 4 cases demonstrated bilateral symmetrical hyperintense areas surrounded by hypointense areas in the globus pallidus giving the characteristic "eye-of-the-tiger" sign. Based on the clinical and MRI picture, these 4 cases could be the atypical type of HSS. However, calcification of globus pallidus is an associated finding in these cases. This is the second report in the literature with this association. In addition, we present the results of the use of antioxidants, L-dopa and Botulinum toxin injections in the management of these cases