Akif Ayaz

Kanuni Sultan Süleyman Training and Research Hospital Istanbul · Department of Medical Genetics

Agammaglobulinemia represents the most profound primary antibody deficiency, stemming from early cessation of B-cell development. Deficiency in folliculin-interacting protein 1 (FNIP1) is a novel inborn error of immunity characterized by a severe defect in B-cell development, agammaglobulinemia, variable neutropenia, and hypertrophic cardiomyopathy...

Although many genetic etiologies, such as Fanconi anemia, Shwachman–Diamond syndrome, dyskeratosis congenita, and Diamond–Blackfan anemia, from hereditary bone marrow failure are known today, the responsible gene remains unknown in a significant part of these patients. A 6-year-old girl, whose parents were first-cousin consanguineous, was referred...

The discovery of low-coverage (i.e. uncovered) regions containing clinically significant variants, especially when they are related to the patient’s clinical phenotype, is critical for whole-exome sequencing (WES) based clinical diagnosis. Therefore, it is essential to develop tools to identify the existence of clinically important variants in low-...

Background: Although the underlying genetic causes of intellectual disability (ID) continue to be rapidly identified, the biological pathways and processes that could be targets for a potential molecular therapy are not yet known. This study aimed to identify ID-related shared pathways and processes utilizing enrichment analyses. Method: In this...

Objective: The study aims to determine what proportion of Turkey’s preoperative patient population has tested positive for COVID-19 and to ascertain whether the increasing or decreasing trend in the numbers of positive preoperative patients resembles the general population of Turkey during the same period. Methods: The study cohort is comprised of...

Objective: Joubert syndrome is a neurodevelopmental disorder with a distinctive hindbrain malformation called molar tooth sign, causing motor and cognitive impairments. More than 40 genes have been associated with Joubert syndrome. We aim to describe a group of Joubert syndrome patients clinically and genetically emphasizing organ involvement. Me...

Objective: Of the existing variants, alpha (B.1.1.7), beta (B.1.351), gamma (P.1), delta (B.1.617.2), and omicron (B.1.1.529) were defined as variants of concern (VOCs) by World Health Organization. We aimed to retrospectively assess the distribution of VOCs in patients with positive COVID-19 real-time polymerase chain reaction (RT-PCR) test. Metho...

Purpose A number of mechanisms have been proposed for the effect of chromosomal translocations on spermatogenesis and sperm maturation. However, there are still numerous ambiguous issues regarding these two processes. The aim of this study is to evaluate the effect of chromosome break areas on sperm count in the light of the literature. Material an...

Familial acute necrotizing encephalopathy (ANE) is is a rapidly progressive encephalopathy that can occur after common viral infections at different stages of life. The clinical findings of 2 siblings diagnosed with ANE were shared and the whole-exome-sequencing study of the index case was performed. It was confirmed by the Sanger method. We found...

Crisponi/cold‐induced sweating syndrome (CS/CISS) is a rare autosomal recessive disorder characterized by episodic hyperthermia, arthrogryposis, impaired feeding ability, and respiratory distress. The classic CS/CISS is mainly associated with CRLF1 and, rarely, CLCF1. PERCHING syndrome, previously known as CS/CISS type‐3 associated with biallelic p...

Objective: In this study, we sought to describe the clinical, laboratory, and genetic character- istics of patients diagnosed with primary hemophagocytic lymphohistiocytosis. Thus, we aimed to evaluate the early diagnosis and appropriate treatment options for pediatric hemophago- cytic lymphohistiocytosis patients. Materials and methods: Medical...

Objective: This study aimed to demonstrate the diagnostic value of microarray testing in autism spectrum disorder, intellectual disability, and multiple congenital anomalies of unknown etiology, as well as to report some potential candidate genes for autism. Methods: Microarray analysis records between January 2016 and December 2017 from two Gen...

Transcriptional coregulators modulate the efficiency of transcription factors. Bi-allelic variants in TRIP4 and ASCC1, two genes that encode members of the tetrameric coregulator ASC-1, have recently been associated with congenital bone fractures, hypotonia, and muscular dystrophy in a total of 22 unrelated families. Upon exome sequencing and data...

Objective: Low estriol (uE3) levels in the second-trimester screening for Down syndrome may be the result of fetal demise, congenital abnormalities, or some genetic hormonal disorders of the fetus. Although X-linked ichthyosis, a microdeletion syndrome with mild ichthyosis, which causes steroid sulfatase (STS) deficiency, is the most common geneti...

Objectives: To describe the clinical characteristics of patients with chronic neutropenia. Methods: Data of 36 patients with chronic neutropenia, who were followed up in the authors' clinic between May 2013 and May 2020, were analyzed retrospectively. Patients were diagnosed based on their clinical and laboratory characteristics. Results: A to...

Background: PNPK gene mutations result in DNA repair disorders and have a spectrum of neurodevelopmental manifestations. To date, cancer predisposition has not been described in patients with PNKP mutations. Observation: Here, we report a patient with PNKP mutation, who developed AML at age of five and underwent reduced-intensity HSCT. Conclusi...

Background Today, it is known that about 80 genes are involved in the etiology of hereditary spastic paraplegia. However, there are many cases whose etiology could not be determined by extensive genetic tests such as whole-exome sequencing, clinical exome. Methods Candidate genes were determined, since no clinically illuminating variant was detect...

Neurexins (NRXNs) are cell-adhesion molecules that play critical roles in establishing and maintaining synaptic connections. Humans have three NRXN genes (NRXN1, NRXN2, NRXN3) and heterozygous intragenic microdeletions involving NRXN1 have been associated with autism spectrum disorder, attention deficit hyperactivity disorder, intellectual disabili...

Neurodevelopmental disorders (NDDs) are clinically and genetically heterogenous; many such disorders are secondary to perturbation in brain development and/or function. The prevalence of NDDs is > 3%, resulting in significant sociocultural and economic challenges to society. With recent advances in family-based genomics, rare-variant analyses, and...

Objective: Our aim is to evaluate how many patients with neuromuscular manifestations get a definite diagnosis and which methods are used in the pathway to diagnosis as well as to assess patient characteristics. Methods: Patients aged 0-18 years old with neuromuscular manifestations (e.g., weakness, hypotonia, creatine kinase elevation) who were ad...

Background: Ovotesticular disorder is characterized by the presence of testicular tissue and ovarian tissue in the same individual. Single gen mutations such as SRY, SOX9, DMRT1 and DAX1 can lead to ovotesticular disorder of sexual development. Case report: Herein, we reported a 3 month-old phenotypically female detected tissues differentiated b...

Rubinstein–Taybi syndrome (RSTS) is a developmental disorder characterized by a wide spectrum of multiple congenital anomalies and cognitive impairment. RSTS is primarily due to mutations in CREBBP (approximately 55% of cases) or EP300 (approximately 8% of cases) genes. A 2 month-old boy had atypical facial findings such as low anterior hairline, t...

Hereditary congenital facial paresis (HCFP) is characterized by isolated dysfunction of the facial nerve (CN VII) due to congenital cranial dysinnervation disorders. HCFP has genetic heterogeneity and HOXB1 is the first identified gene. We report the clinical, radiologic and molecular investigations of three patients admitted for HCFP in a large co...

Caffey disease is a rare condition of early infancy, characterized by soft tissue swelling, bone lesions, and hyperirritability. Its typical radiological finding is periosteal new bone formation. It can be sporadic or inherited in an autosomal dominant manner. There is no specific treatment. In symptomatic cases, non-steroidal anti-inflammatory dru...

BACKGROUND AND AIM:The focal facial dermal dysplasias are a group of inherited, rare disorders of facial development characterized by bitemporal or preauricular scar-like defects resembling ‘forceps marks’. Four subtypes have been delineated, and the mutations in the TWIST2 gene have been identified in type-III focal facial dermal dysplasia, Setlei...

BACKGROUND AND AIM:The male factor has been shown to be the primary cause of infertility in 30-50% of couples. Chromosomal abnormalities are considered to be a major cause of male infertility. Structural and numerical chromosomal abnormalities have been reported in 10-23.62% of the males with azoospermia and in 1.10-13.33% of the males with oligosp...

BACKGROUND AND AIM:Tetrasomy 18p is one of the most commonly reported isochromosomes [i(18p)] affecting both genders equally. The prevalent mechanism lying at the background of the vast majority of reported cases is de novo nondisjunction followed by centromeric misdivision during maternal meiosis II (MII). Here we report de novo tetrasomy 18p and...

α-thalassemia is the most common single gene disorder in the Cukurova Region in Turkey. It is therefore routinely screened, including premaritally, in our region. The heterogeneous molecular basis of the disease makes α-thalassemia mutation detection difficult and complex. Besides well established methods, multiplex ligation dependent probe amplifi...

Objective: To date, studies in all populations showed that mutations in the gene of Gap junction protein beta 2 (GJB2) play an important role in non-syndromic autosomal recessive congenital hearing loss. The aim of this study was to evaluate GJB2 gene of patients with hearing loss in our region using deoxyribonucleic acid (DNA) sequencing method a...

Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease and chromosomal abnormalities with prognostic impact are frequently detected in CLL patients. There are a variety of characterized chromosomal abnormalities detected by conventional cytogenetics in CLL. These abnormalities are valuable prognostic indicators and important key s...