Severe complications in a child with achondroplasia and two FGFR3 mutations on the same allele

We describe a unique case of achondroplasia with associated complications, including severe respiratory problems. Molecular analysis of the fibroblast growth factor receptor type 3 (FGFR3) gene in this patient showed the common p.G380R mutation and a second novel p.L377R mutation. An allele-specific PCR demonstrated that these mutations were on the same allele (cis). Both mutations were not present in the parents and appear to have occurred de novo. To our knowledge, this is the first report in the literature on an achondroplasia patient with two FGFR3 mutations on the same allele

Feasibility and outcomes of multiplex ligation-dependent probe amplification on buccal smears as a screening method for microdeletions and duplications among 300 adults with an intellectual disability of unknown aetiology

Background Determining the actiology of intellectual disability (ID) enables anticipation of specific comorbidity and can thus be beneficial. Blood sampling, however, is considered stressful for people with ID. Our aim was to evaluate the feasibility of a non-invasive screening technique of nine microdeletions/duplications among adults with ID of unknown aetiology. Methods In a random sample Of 300 adult clients of Dutch ID services without an aetiological diagnosis, DNA was collected on site using oral swabs. Multiplex Ligation-dependent Probe Amplification was applied to screen for nine microdeletions/ duplications related to ID syndromes (Williams 22q11-deletion, 1p-deletion, Miller-Dieker, Smith-Magenis, Prader-Willi, Alagille, Saethre-Chotzen and Sotos syndrome). Results Feasibility: prior to the consent procedure, for 2.1% (10/471 eligible participants), the method was considered undesirable. In 0.7% (2/300 participants) oral swabs failed because of resistant behaviour, while in 16.1% (48/298 swabs) analysis was unsuccessful because of insufficient amounts of DNA. A repeated attempt yielded an equal success rate. Outcome Microdeletions were diagnosed in four participants: 22q11 deletion (n = 2), 5q35 deletion (Sotos syndrome) (n = 1) and 1p deletion (n = 1). One participant had a duplication of the Prader Willi Region (15q11-13) owing to mosaicism of a supernumerary marker chromosome (15). Conclusions Oral swabs are a feasible method for DNA sampling in adults with IDs. A diagnosis could be made in five Out Of 275 people with ID of unknown aetiology. After screening, in the total population sample (n = 620), the prevalence of syndromes associated with the microdeletions/ duplications studied was at least 2.3% (95% confidence interval 1.1-3.4%)

Comparing two diagnostic laboratory tests for Williams syndrome: Fluorescent in situ hybridization versus multiplex ligation-dependent probe amplification

Most people with Williams syndrome (WS) have a heterozygous 1.55 Mb deletion on chromosome 7q11.23. For diagnostic purposes, fluorescence in situ hybridisation (FISH) with commercial FISH probes is commonly used to detect this deletion. We investigated whether multiplex ligation-dependent probe amplification (MLPA) is a reliable alternative for FISH. The MLPA kit (SALSA P029) contains probes for eight genes in the WS critical region: FKBP6, FZD9, TBL2, STX1A, ELN, LIMK1, RFC2, and CYLN2. The experimental FISH assay that was used consists of four probes covering the WS critical region. A total number of 63 patients was tested; in 53 patients, a deletion was detected both with FISH and MLPA(P029), in 10 patients both techniques failed to demonstrate a deletion. In only one patient, a deletion was detected which was not previously detected by two commercial FISH probes. This patient appeared to carry a small, atypical deletion. We conclude that MLPA is a reliable technique to detect WS. Compared with FISH, MLPA is less time consuming and has the possibility to detect also smaller, atypical deletions and duplications in the WS critical region

Optimization of performance of Dutch newborn screening for cystic fibrosis.

Dutch protocol consists of four steps: determination of immunoreactive trypsinogen (IRT) and pancreatitis-associated protein (PAP), DNA analysis by INNO-LiPA and extended gene analysis (EGA). For the optimization phase we used results of 556,952 newborns screened between April 2011 and June 2014 to calculate effects of 13 alternative protocols on sensitivity, specificity, PPV, ratios of CF to other diagnoses, and costs. One alternative protocol was selected based on calculated sensitivity, PPV and costs and was implemented on 1st July 2016. In this modified protocol DNA analysis is performed in samples with a combination of IRT ≥60 µg/l and PAP ≥3.0 µg/l, IRT ≥100 µg/l and PAP ≥1.2 µg/l or IRT ≥124 µg/l and PAP not relevant. Results of 599,137 newborns screened between 1st July 2016 and 31st December 2019 were similarly evaluated as in the optimization phase

Relative frequency and morphology of cancers in STK11 mutation carriers

Relative frequency and morphology of cancers in STK11 mutation carriers Background & Aims: There is limited data on the spectrum and risk for cancer associated with germline serine/threonine protein kinase 11 (STK11) mutations that cause Peutz-Jeghers syndrome (PJS). Methods : We analyzed the incidence of cancer in 240 individuals with PJS possessing germline mutations in STK11. Results: Fifty-four cancers were found among carriers. Overall, the risk for developing cancer at ages 20, 30, 40, 50, 60, and 70 years was 1%, 3%, 19%, 32%, 63%, and 81%, respectively. Kaplan-Meier analysis showed similar cancer risks between missense and truncating mutation carriers (log-rank chi(2) = 2.48; P = 0.12). There was some evidence that mutations in exon 3 of STK11 were associated with a higher cancer risk than mutations within other regions of the gene. We found no difference in overall cancer risk between male and female carriers (log-rank chi(2) = 1.31; P = 0.25) or between familial and sporadic cases (log-rank chi(2) = 1.16, with 1 df; P = 0.28). The most common cancers represented were gastrointestinal in origin-gastroesophageal, small bowel, colorectal, and pancreatic-and the risk for these cancers at ages 30, 40, 50, and 60 years was 1%, 10%, :18%, and 42%, respectively. In women, the risk for breast cancer was substantially increased, being 32% by age 60 years. Conclusions: These results quantitatively show the spectrum of cancer risk associated with STK11 germline mutations in the context of PJS and provide a valuable reference for defining surveillance regimens