|
|
Research Papers
|
Epidemiology of Van der Woude syndrome
from mutational analyses in affected patients from Pakistan |
Malik S, Kakar N, Hasnain S,
Ahmad J, Wilcox ER, Naz S
Abstract
Epidemiology of Van der Woude syndrome from mutational analyses in
affected patients from Pakistan. Clin Genet 2010: 78: 247–256. © John Wiley &
Sons A/S, 2010 Mutations in IRF6 cause Van der Woude syndrome (VWS), one of the
most common syndromes associated with cleft lip (CL) with or without cleft
palate (CP). The presence of pits on the lower lip of patients is the most
characteristic feature of the syndrome. We have identified three novel and seven
previously reported IRF6 mutations in 12 of 16 unrelated families segregating
VWS from Pakistan. The three newly identified mutations include a frameshift
(c.568delG) and two missense mutations c.295G>A (p.G99S) and c.1219T>C
(p.S407P). Recent functional studies on IRF6 and the three-dimensional structure
of IRF5 carboxy (C) terminus, a protein encoded by a paralog of IRF6, shed light
on the p.S407P substitution. Additionally, the identification of the same
mutations responsible for VWS in Pakistan, as reported in other global
populations worldwide, marks these residues as mutational hotspots and indicates
their essential role in structural stability or function of IRF6. This is the
first study of VWS in Pakistan and we estimate that 1 in 100 patients with CL
with or without CP (CL/P) are affected in the Pakistani population predominantly
from the Punjab area.
|
|
Prevalence of hepatitis Cvirus (HCV) genotypes
in Balochistan |
Sarwat Afridi, Muhammad Naeem,
Abid Hussain, Naseebullah Kakar,
Masroor Ellahi Babar, Jamil Ahmad
Abstract
A molecular study was conducted to investigate the prevalence of Hepatitis
C virus genotypes in HCV infected population of Balochistan. Forty HCV seropositive
samples belonging to seven different locations of Balochistan were collected from
different health care centres. Qualitative analysis of these samples using PCR resulted
in 28 positive samples. The PCR positive samples were subjected to genotyping using
the method described by Ohno et al (J Clin Microbiol 35:201–202, 1997) with minor
modifications. Genotyping of 28 samples revealed three different genotypes including
3a, 3b and 1a. The most prevalent genotype was 3a with rate of 50% followed by genotype
3b and 1a, respectively. Nine samples remained untyped, suggesting the need of further
investigation of genotypes in this region. It has been proposed that sequencing
of these samples may be helpful to unreveal these genotypes and further epidemiology
of HCV genotypes. Further more, extensive and large scale studies are needed to
understand the epidemiology of HCV genotypes, as no such study has been carried
in this province.
|
|
A novel HSF4 gene mutation (p.R405X) causing
autosomal recessive congenital cataracts in a large consanguineous family from Pakistan
|
Naheed Sajjad, Ingrid Goebel,
Naseebullah Kakar, Abdul Majeed Cheema,
Christian Kubisch and Jamil Ahmad
Abstract
Background: Hereditary cataracts are most frequently inherited as autosomal
dominant traits, but can also be inherited in an autosomal recessive or X-linked
fashion. To date, 12 loci for autosomal recessive cataracts have been mapped including
a locus on chromosome 16q22 containing the disease-causing gene HSF4 (Genbank accession
number NM_001040667). Here, we describe a family from Pakistan with the first nonsense
mutation in HSF4 thus expanding the mutational spectrum of this heat shock transcription
factor gene.
Methods: A large consanguineous Pakistani family with autosomal
recessive cataracts was collected from Quetta. Genetic linkage analysis was performed
for the common known autosomal recessive cataracts loci and linkage to a locus containing
HSF4 (OMIM 602438) was found. All exons and adjacent splice sites of the heat shock
transcription factor 4 gene (HSF4) were sequenced. A mutation-specific restriction
enzyme digest (HphI) was performed for all family members and unrelated controls.
Results: The disease phenotype perfectly co-segregated with markers
flanking the known cataract gene HSF4, whereas other autosomal recessive loci were
excluded. A maximum two-point LOD score with a Zmax = 5.6 at θ = 0 was obtained
for D16S421. Direct sequencing of HSF4 revealed the nucleotide exchange c.1213C
> T in this family predicting an arginine to stop codon exchange (p.R405X).
Conclusion: We identified the first nonsense mutation (p.R405X)
in exon 11 of HSF4 in a large consanguineous Pakistani family with autosomal recessive
cataract.
|
|