Genetic analysis of a Chinese pedigree with Lesch-Nyhan syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic etiology for a Chinese pedigree affected with Lesch-Nyhan syndrome.@*METHODS@#Members of the pedigree who had visited the Genetic Counseling Clinic of Linyi People's Hospital on February 10, 2022 were selected as the study subjects. Clinical data and family history of the proband were collected, and trio-whole exome sequencing (trio-WES) was carried out for the proband and his parents. Candidate variants were verified by Sanger sequencing.@*RESULTS@#Trio-WES revealed that both the proband and his cousin brother had harbored a hemizygous c.385-1G>C variant in intron 4 of the HPRT1 gene, which was unreported previously. A heterozygous c.385-1G>C variant of the HPRT1 gene was also found in the proband's mother, grandmother, two aunts, and a female cousin, whilst all phenotypically normal males in his pedigree were found to have a wild type for the locus, which has conformed to an X-linked recessive inheritance.@*CONCLUSION@#The heterozygous c.385-1G>C variant of the HPRT1 gene probably underlay the Lesch-Nyhan syndrome in this pedigree.

Uma nova estratégia para o diagnóstico de mulheres portadoras de mutações que causam a síndrome de LESCH-NYHAN

A síndrome de Lesch-Nyhan é uma entidade clínica que apresenta um padrão de herança recessivo ligado ao cromossomo X. Pertence ao grupo dos erros inatos do metabolismo e é originada por uma deficiência absoluta da enzima hipoxantina-guanina fosforibosiltransferase (HPRT1; EC 2.4.2.8). Mulheres heterozigotas para mutações HPRT1 que causam a síndrome de Lesch-Nyhan podem ser detectadas mediante análises moleculares de híbridos celulares somáticos derivados da fusão de Iinfócitos de sangue periférico e células Hprt-negativas provenientes de roedor com a subseqüente seleção em meio de cultura contendo hipoxantina, aminopterina e timidina (HAT). A origem parental do cromossomo X contendo o alelo HPRT1 normal em linhagens celulares híbridas HPRT1 + pode ser determinada por haplótipos moleculares demonstrados por marcadores altamente polimórficos ligados ao cromossomo X. Esta metodologia foi utilizada para estudar uma possível heterozigota cujo cromossomo X paterno ativo esta sempre presente nas linhagens celulares derivadas dela. Contrariamente, o cromossomo X materno esteve sistematicamente ausente na maioria dos híbridos, e quando presente, estava inativo coexistindo com um X paterno ativo. Sub-clones sem o X paterno ativo e contendo o X materno inativo, não apresentaram atividade HPRT1 quando tratados com 5-aza-citidina. A ausência de transcrito do HPRT1 após o tratamento foi comprovada mediante RT-PCR. Estes resultados claramente demonstraram que a probanda é portadora de uma mutação responsável pela deficiência de HPRT1

Lesch-Nyhan syndrome is a recessive X-Iinked metabolic disorder resulting from absolute deficiency of the enzyme hypoxanthine/guanine phosphoribosy/transferase (HPRT1; EC 2.4.2.8). Heterozygous carriers of HPRT1 mutations responsible for Lesch-Nyhan syndrome can be detected by analysis of somatic cell hybrids derived from peripheral blood Iymphocytes and Hprt-negative cells of rodent origin followed by selection in culture medium containing hypoxanthine, aminopterine, and thymidine (HAT). The parental origin of the X chromosome containing the normal HPRT1 allele in HPRT1 + hybrid cell lines can be determined by molecular haplotyping attributable to highly polymorphic X-Iinked markers. We used this procedure to study a presumed carrier whose paternal active X chromosome always segregated in the cell hybrids derived from her. Conversely, her maternal X chromosome was systematically absent in most of cell hybrids, or when present, it was inactive and coexisted with an active, paternal X chromosome. Sub-clones lacking the paternal, active X chromosome and containing the X inactive maternal chromosome were unable to reactivate the HPRT1 locus following treatment with 5-aza-eytidine. HPRT1 transcripts were found to be absent with RT -PCR. These results c1early demonstrated that the proband was a heterozygous carrier of a mutation responsible for HPRT1 deficiency

Identification of a new lesch syndrome mutation (HPRT BRASIL) and analysis of pontentially heterozygous females

The mutation in the hypoxanthine-guanine phosphoribosyltransfere (HPRT) gene has been determined in two brothers affected with Lesch-Nyhan syndrome. Female members of the family who are at risk for being heterozygous carriers of the HPRT mutation were also studied to determine whether they carry the mutation. DNA sequencing revealed that the boys' mother heterozygous for the mutation in her somatic cells, but that three maternal aunts are not heterozygous. Such carrier information is important for the future pregnancy plans of at-risk females. The mutation, an A_T transversion at cDNA base 590 (590 A_T), results in an amino acid change of glutamic acid to valine at codon 197, and has not been reported previously in a Lesch-Nyhan syndrome male. This mutation is designated HPRT.

Síndrome de Lesch-Nyhan incompleto : comunicación del primer caso argentino / Incomplete Lesch-Nyhan syndrome : communication of first case argentinian

El síndrome de Lesch-Nyhan es una infrecuente gota hereditaria vinculada al déficit virtualmente completo de la enzima hipoxantina guanina fosforribosil transferasa (HGFT) existiendo ocasionalmente déficit parciales, que se diferencian de las formas completas por presentar manifestaciones neuropsiquiátricas menores. Es nuestro objetivo presentar al que en nuestro conocimiento es el primer paciente argentino portador del síndrome de Lesh-Nyhan incompleto o de Kelley-Seegmiller. Paciente varón de 38 años con historia familiar de gota e insuficiencia renal que desarrolla una severa artritis gotosa tofácea de rápida evolución y déficit intelectual. Los análisis de laboratorio de rutina mostraron una marcada hiperuricemia y excesiva excreción de ácido úrico con una función renal conservada. La determinación de la actividad enzimática de la HGFT se halló francamente disminuida.

Aspectos clínicos y bioquímicos del síndrome de Lesch-Nyhan

El síndrome de Lesch-Nyhan es una enfermedad genética ligada al cromosoma X, originada por un defecto en el gen que codifica la hipoxantia guanina fosforribosiltransferasa (HGPRT). Esta enzima participa en la recuperación de la guanina e hipoxantina. La deficiencia enzemática conlleva una acumulación exagerada del ácido úrico. La deficiencia total o casi total de la enzima, produce el síndrome de Lesch-Nyhan, el cual se caracteriza por hiperruricemia, hiperaciduria, coreoatetosis, hiperreflexia, retardo mental y autoagresividad. La deficiencia parcial de la enzima ocasiona artritis gotosa y nefrolitiasis sin daño neurológico.

Enfermedad de Lesch-Nyhan / Lesch-Nyhan disease

Se presenta un caso de Enfermedad de Lesch-Nyhan típico, cuyo diagnóstico fue confirmado a través de técnicas de crecimiento celular diferencial. Esta técnica permitió también establecer la condición de portadora en la madre y una de las tías en la que se realizó el diagnóstico prenatal de un nuevo caso. Se revisan algunos aspectos clínicos, metabólicos y terapéuticos de interés, enfatizando la importancia de los estudios diagnósticos específicos para el consejo genético adecuado de familias con esta rara pero grave enfermedad