Doença de Tay-Sachs: relato de caso / Tay-Sachs disease: a case report

RESUMO A doença de Tay-Sachs é um distúrbio neurodegenerativo autossômico recessivo, o qual envolve o metabolismo dos lipídios, levando ao acúmulo de gangliosídeos nos tecidos, devido à deficiência da enzima hexosaminidase A. Esse depósito progressivo resulta em perda da função neurológica e, quando acomete as células ganglionares da mácula, causa o achado típico da doença, a "mácula em cereja". A patologia é diagnosticada por meio dos níveis de hexosaminidase A e hexosaminidase total no soro, além análise do DNA do gene HEXA. Este caso relata uma criança com doença de Tay-Sachs cujo diagnóstico foi suspeitado por conta dos achados oftalmológicos.

ABSTRACT Tay-Sachs Disease is an autosomal recessive neurodegenerative disorder, which involves the metabolism of lipids, leading to the accumulation of gangliosides in the tissues, due to the deficiency of the enzyme Hexosaminidase A. This progressive deposit results in loss of neurological function and, when it affects macula ganglion cells, it causes the typical disease finding, the "cherry red spot". The pathology is diagnosed through the levels of Hex A and total Hexosaminidase in the serum, in addition to the analysis of the DNA of the HEXA gene. This case reports a child with Tay-Sachs disease with a suspected diagnosis was through ophthalmologic findings.

Progressive psychomotor regression for 2.5 years in a boy aged 5 years / 中国当代儿科杂志

A boy, aged 5 years, attended the hospital due to progressive psychomotor regression for 2.5 years. Motor function regression was the main manifestation in the early stage, and brain MRI and whole-exome sequencing (WES) of the family showed no abnormalities. After the age of 4 years and 9 months, the boy developed cognitive function regression, and brain MRI showed cerebellar atrophy. The reanalysis of WES results revealed a compound heterozygous mutation, [NM_000520, c.784C>T(p.His262Tyr]), c.1412C>T(p.Pro471Leu)], in the HEXA gene. The enzyme activity detection showed a significant reduction in the level of β-hexosaminidase encoded by this gene. The boy was diagnosed with juvenile Tay-Sachs disease (TSD). TSD has strong clinical heterogeneity, and cerebellar atrophy may be an important clue for the diagnosis of juvenile TSD. The reanalysis of genetic data when appropriate based on disease evolution may improve the positive rate of WES.

Comparison of enzyme and DNA analysis in a Tay-Sachs disease carrier screening program

Tay-Sachs disease (GM2 gangliosidosis, type 1; TSD) is an autosomal recessive GM2 gangliosidosis resulting from the deficient activity of the lysosomal hydrolase beta-hexosaminidase A (Hex A). With a carrier frequency estimated at 1 in 25, it is a common lysosomal disorder in the Ashkenazi Jewish population. Tay-Sachs disease has provided the prototype for the prevention of severe recessive genetic diseases. Molecular analysis of the Hex A gene (HEXA) of Ashkenazi Jewish individuals affected with Tay-Sachs disease revealed that three common mutations cause the infantile and adult onset forms of the disease; a four base insertion in exon 11, a splice junction mutation in intron 12 and a point mutation in exon 7 (G269S). A study was undertaken to determine whether mutation analysis would be useful in TSD screening programs in identifying carriers and clarifying the status of individuals whose enzyme assays are inconclusive. Ashkenazi Jewish individuals who had been diagnosed as carriers, inconclusives by enzyme assay and non-carriers with low normal enzyme levels in the Mount Sinai Tay-Sachs Disease Prevention Program were examined for the presence of the three mutations using polymerase chain reaction (PCR) and allele specific oligonucleotide (ASO) hybridization. The insertion mutation was present in 29 of 34 carriers and 2 of 36 inconclusive individuals, the splice junction mutation was found in 4 of 34 carriers and the G269S mutation was found in 1 of 34 carriers. Of the 313 non-carrier individuals with normal enzyme activity in the lower normal range, one was positive for the splice junction mutation.(ABSTRACT TRUNCATED AT 250 WORDS)