Exocrine The most prominent effect of<unk>  is pancreatic exocrine insufficiency. Varying degrees of decreased secretion of lipases, pancreatic juices such as trypsin, trypsinogen and others, as well as malabsorption of fats and disruptions of glucagon secretion and its response to hypoglycemia caused by insulin activity are major concerns when<unk>  is diagnosed. Associated with developmental errors, impaired apoptosis, and both prenatal and chronic inflammatory damage, necrosis and fibrosis of the pancreatic acini (clusters of pancreatic exocrine gland tissue, where secretion of pancreatic juice and related enzymes occurs), pancreatic exocrine insufficiency in<unk>  can additionally stem from congenital replacement of the acini with fatty tissue. Near total replacement of the entire pancreas with fatty tissue has also been reported. This is a progressive, sometimes fatal consequence of the disorder. Endocrine Endocrine insufficiency of the pancreas occurs with<unk> , though it is sometimes less common and less pronounced than the more prominent effects on exocrine function. The islets of Langerhans are ducts in the pancreas where endocrine activity such as the release of hormones glucagon, somatostatin and insulin takes place. Pancreatic endocrine insufficiency in<unk>  can be associated with either a buildup of connective tissue in the islet regions, congenital replacement of the islets with fatty tissue, or improper nerve signalling to the islets. Endocrine dysfunction of the pancreas often results in diabetes mellitus. Both insulin resistance and diabetes have been observed with<unk> , and it is suggested that diabetes should be considered as a complication of<unk>  and its course. Ductular output of fluids and electrolytes is preserved in the pancreas of many with<unk> , as well as moderate to normal levels of functioning bicarbonate. Endocrine abnormalities in other areas have also been present with the disorder. These include hypothyroidism, growth hormone deficiency and hypopituitarism. Findings affecting pituitary function in some<unk>  patients have included such anomalies as the formation of a glial hamartoma (a neoplasm, or tumor composed of glial cells) on a lobe of the pituitary gland, as well congenital underdevelopment of the anterior pituitary. Growth failure and associated short stature (dwarfism) in<unk>  can be attributed to growth hormone deficiency caused by diminished anterior pituitary function, with malabsorption of fats playing a subsequent role. Nasopharyngeal Pharyngeal malformations can lead to food passing through the nose The primary malformation apparent with<unk>  is hypoplasia (underdevelopment) of the nasal alae, or "wing of the nose". Both hypoplasia and aplasia (partial or complete absence) of structural cartilage and tissue in this area of the nose, along with the underlying alae nasi muscle, are prevailing features of the disorder. Together, these malformations give the nose and nostrils an odd shape and appearance. Neurological Intellectual disability ranging from mild to severe is present in the majority of<unk>  patients, and is related to the deleterious nature of the known mutagen responsible for the disorder and its effects on the developing central nervous system. Normal intelligence and age appropriate social development, however, have been reported in a few instances of<unk> . Auditory Findings with the inner ear in<unk>  give explanation to the presence of bilateral sensorineural hearing loss in most patients affected by the disorder. The formation of cystic tissue in both the cochlea and vestibule, with resulting dilation (widening) and malformation of these delicate structures has been implicated. Congenital deformations of the temporal bone and associated adverse anatomical effects on innervation and development of the inner ear also contribute to this type of hearing loss. Craniofacial Other abnormalities, affecting the scalp, head, face, jaw and teeth may be found with JBS. These include: ectodermal mid-line scalp defects with sparse, oddly-patterned hair growth; aplasia cutis (underdeveloped, very thin skin) over the head, an enlarged fontanelle ("soft spot" on the head of young infants), microcephaly (undersized skull), prominent forehead, absence of eyebrows and eyelashes, mongoloid eye shape, nasolacrimo- cutaneous fistulae (this refers to the formation of an abnormal secondary passageway from either the tear duct or lacrimal sac to the facial skin surface, possibly discharging fluid), flattened ears, micrognathism of the maxilla and mandible (underdevelopment of the upper and lower jaw, respectively), with the maxilla more prominently affected in some cases; congenital clefting of bones surrounding the optical orbit (eye socket), such as the frontal and lacrimal bone; and maldeveloped deciduous teeth ("baby teeth"), with an absence of permanent teeth. Effects on other organ systems Additional congenital anomalies, effects on other organs, and less common features of JBS have included: imperforate anus (occlusion of the anus), vesicoureteral reflux (reversal of the flow of urine, from the bladder back into the ureters, toward the kidneys); duplex of the uterus and vagina in female infants, neonatal cholestasis of the liver, with cirrhosis and portal hypertension (high blood pressure in the hepatic portal vein); dilated cardiomyopathy, dextrocardia (congenital displacement of the heart to the right side of the chest), atrial and ventricular septal defect; low birth-weight, failure to thrive, hypotonia (decreased muscle tone); sacral hiatus (a structural deficiency of the sacral vertebrae), congenital cataracts, and cafe-au-lait spots.
Johanson–Blizzard syndrome
Cystic fibrosis
Gómez–López-Hernández syndrome
Secretan's syndrome
Fitz-Hugh–Curtis syndrome
Naegeli–Franceschetti–Jadassohn syndrome
Lucey–Driscoll syndrome
Zollinger–Ellison syndrome