[Prenatal diagnosis and genetic counseling in two pedigrees affected with infantile polycystic kidney disease due to PKHD1 gene mutations].

OBJECTIVE: To detect potential mutations of the PKHD1 gene in two pedigrees affected with infantile polycystic kidney disease. METHODS: Clinical data and peripheral venous blood samples were collected from the probands and their parents as well as fetal amniotic fluid cells. Genome DNA was extracted from the peripheral blood samples and amniotic fluid cells. Exons 32 and 61 of the PKHD1 gene were amplified with PCR and subjected to direct sequencing. RESULTS: The proband of pedigree 1 was found to carry c.4274T>G (p.Leu1425Arg) mutation in exon 32 and c.10445G>C (p.Arg3482Pro) mutation in exon 61 of the PKHD1 gene, which were inherited from her father and mother, respectively. The fetus has carried the c.4274T>G (p.Leu1425Arg) mutation. In pedigree 2, the wife and her husband had respectively carried a heterozygous c.5979_5981delTGG mutation and a c.9455delA mutation of the PKHD1 gene. No chromosomal aberration was found in the umbilical blood sample, but the genetic testing of their fetus was failed. Based on software prediction, all of the 4 mutations were predicted to be pathogenic. CONCLUSION: PKHD1 c.4274T>G (p.Leu1425Arg), c.10445G>C (p.Arg3482Pro), c.5979_5981delTGG and c.9455delA were likely to be pathogenic mutations. The results have facilitated genetic counseling and prenatal diagnosis for the two pedigrees.

A study of deafness-related genetic mutations as a basis for strategies to prevent hereditary hearing loss in Hebei, China.

Hearing loss is the most common sensory disorder, and at least 50% of cases are due to a genetic etiology. Two-thirds of individuals with congenital deafness are nonsyndromic. Among the nonsyndromic forms, the large majority are monogenic autosomal recessive traits. The current work summarizes mutations in the GJB2, SLC26A4, 12SrRNA, and GJB3 and their prevalence in 318 students with autosomal recessive nonsyndromic hearing loss at schools for the deaf or special needs schools in 9 cities in Hebei Province, China. Deafness gene mutations were identified in 137 students via a gene chip, time-of-flight mass spectrometry, fluorescence quantitative PCR, and gene sequencing. Mutations were detected at a rate of 43.08%. A homozygous mutation of the GJB2 gene was found in 16 students (5.03%), a heterozygous mutation of that gene was found in 38 (11.95%), a homozygous mutation of the SLC26A4 gene was found in 22 (6.92%), a heterozygous mutation of that gene was found in 59 (18.55%), and a heterozygous mutation of the mitochondrial 12SrRNA gene was found in 2 (0.63%). In addition, there were 15 families in which a student's parents had normal hearing. Compound heterozygous mutations of the GJB2 gene were found in 3 families (20%) and mutations of the SLC26A4 gene were found in 9 (60%). Thus, this study has provided a molecular diagnostic basis for the causes of deafness, and this study has also provided a scientific basis for the early prevention of and intervention in deafness.