Dataset Information

The genotype and phenotype of chromosome 18p deletion syndrome: Case series.

ABSTRACT:

Rationale

The chromosome 18p deletion syndrome is a syndrome with a deletion of all or a portion of the short arm of the chromosome 18. The phenotypes of the chromosome 18p deletion syndrome vary widely among individuals due to differences in size and breakpoints and the involved genes on the deletions. Given the varied and untypical clinical presentation of this syndrome, the prenatal diagnosis of the syndrome still presents as a challenge.

Patient concerns

We described 4 China cases with different chromosomal breakpoints. In case 1, a woman who with mild phenotypes gave birth to a severely deformed fetus. Three other cases were for prenatal diagnosis. Their phenotypes are the increased nuchal translucency (INT) and the noninvasive prenatal testing (NIPT) indicated deletions on the chromosome 18p and severe hydronephrosis respectively.

Diagnosis

The 4 cases were diagnosed with chromosome 18p deletion syndrome through karyotype analysis and array-based comparative genomic hybridization (array-CGH).

Interventions

Karyotype analysis and array-based comparative genomic hybridization were used to analyze the abnormal chromosome.

Outcomes

Case 1 and case 2 revealed 11.51 and 12.39 Mb deletions in 18p11.32p11.21. Case 3 revealed 7.1 Mb deletions in 18p11.3218p11.23. Case 4 revealed 9.9 Mb deletions in 18p11.3218p11.22.

Lessons

In our report, we are the first to report that mother and progeny who have the same chromosomal breakpoint have different phenotypes, significantly. In addition, we found a new phenotype of chromosome 18p deletion syndrome in fetus, which can enrich the phenotypes of this syndrome in the prenatal diagnosis. Finally, we demonstrate that the individuals with different chromosomal breakpoints of 18p deletion syndrome have different phenotypes. On the other hand, the individuals with the same chromosomal breakpoints of 18p deletion syndrome may also have remarkably different phenotypes.

SUBMITTER: Jin Q

PROVIDER: S-EPMC8104293 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:PurposeAchromatopsia is a rare stationary retinal disorder that primarily affects the cone photoreceptors. Individuals with achromatopsia present with photophobia, nystagmus, reduced visual acuity (VA), and color blindness. Multiple genes responsible for achromatopsia have been identified (e.g. cyclic nucleotide-gated channel subunit alpha 3 [CNGA3] and activating transcription factor 6). Studies have assessed the role of gene therapy in achromatopsia. Therefore, for treatment and prevention, the identification of phenotypes and genotypes is crucial. Here, we described the clinical manifestations and genetic mutations associated with achromatopsia in patients from Saudi Arabia.MethodsThis case series study included 15 patients with clinical presentations, suggestive of achromatopsia, who underwent ophthalmological and systemic evaluations. Patients with typical achromatopsia phenotype underwent genetic evaluation using whole-exome testing.ResultsAll patients had nystagmus (n = 15) and 93.3% had photophobia (n = 14). In addition, all patients (n = 15) had poor VA. Hyperopia with astigmatism was observed in 93.3% (n = 14) and complete color blindness in 93.3% of the patients (n = 14). In the context of family history, both parents of all patients (n = 15) were genetic carriers, with a high consanguinity rate (82%, n = 9 families). Electroretinography showed cone dysfunction with normal rods in 66.7% (n = 10) and both cone-rod dysfunction in 33.3% (n = 5) patients. Regarding the genotypic features, 93% of patients had variants in CNGA3 (n = 14) categorized as pathogenic Class 1 (86.7%, n = 13). Further, 66.7% (n = 10) of patients also harbored the c.661C>T DNA variant. Further, the patients were homozygous for these mutations. Three other variants were also identified: c.1768G>A (13.3%, n = 2), c.830G>A (6.6%, n = 1), and c. 822G >T (6.6%, n = 1).ConclusionConsanguinity and belonging to the same tribe are major risk factors for disease inheritance. The most common genotype was CNGA3 with the c.661C>T DNA variant. We recommend raising awareness among families and providing genetic counseling for this highly debilitating disease.