Cri-du-chat Syndrome

Epidemiology and Etiology

Epidemiology

• More common in females, with a ratio of 2:1
• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency ranges from 1 in 15,000–50,000 live births

Etiology

• Cri-du-chat syndrome is caused by deletions in the terminal short arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 5 (can affect from only the region 5p15.3 to the entire short arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 5).
  • 5p monosomy Monosomy The condition in which one chromosome of a pair is missing. In a normally diploid cell it is represented symbolically as 2n-1. Types of Mutations, leading to a karyotype Karyotype The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere. Congenital Malformations of the Female Reproductive System of 46,XX or XY,5p‑
  • Partial monosomy Monosomy The condition in which one chromosome of a pair is missing. In a normally diploid cell it is represented symbolically as 2n-1. Types of Mutations
    • 80% of cases are sporadic Sporadic Selective IgA Deficiency ( de novo mutations De novo mutations DiGeorge Syndrome).
    • 10%–15% of cases are originated by parental balanced translocation.
    • < 10% of cases are associated with rare cytogenetic aberrations.
• Deletion in chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 5 is paternal in origin in most cases (80%–90%).
• Genes Genes A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. DNA Types and Structure that contribute to cri-du-chat:
  • Telomerase Telomerase An essential ribonucleoprotein reverse transcriptase that adds telomeric DNA to the ends of eukaryotic chromosomes. DNA Replication reverse transcriptase Reverse transcriptase A reverse transcriptase encoded by the pol gene of HIV. It is a heterodimer of 66 kda and 51 kda subunits that are derived from a common precursor protein. The heterodimer also includes an RNAse h activity that plays an essential role the viral replication process. HIV Infection and AIDS gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics (hTERT), located at 5p13.33 (the short arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 5 at band 13.33), is associated with the phenotypic changes.
  • Semaphorin F gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics (SEMA5A) and delta catenin gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics (CTNND2) at 5p15.2 are involved in cerebral development.

Clinical Presentation

Symptoms vary and depend on the amount of deleted genetic material.

Neonatal symptoms

• The syndrome is named for its characteristic “meow-like” cry of affected infants caused by laryngeal and nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification problems. It lasts for the first few weeks of life.
• Dysphagia Dysphagia Dysphagia is the subjective sensation of difficulty swallowing. Symptoms can range from a complete inability to swallow, to the sensation of solids or liquids becoming “stuck.” Dysphagia is classified as either oropharyngeal or esophageal, with esophageal dysphagia having 2 sub-types: functional and mechanical. Dysphagia
• Low birth weight and poor growth, due to:
  • Failure to thrive Failure to Thrive Failure to thrive (FTT), or faltering growth, describes suboptimal weight gain and growth in children. The majority of cases are due to inadequate caloric intake; however, genetic, infectious, and oncological etiologies are also common. Failure to Thrive
  • Feeding problems due to low muscle tone Muscle tone The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. Skeletal Muscle Contraction, poor suckling, and gastroesophageal reflux disease Gastroesophageal Reflux Disease Gastroesophageal reflux disease (GERD) occurs when the stomach acid frequently flows back into the esophagus. This backwash (acid reflux) can irritate the lining of the esophagus, causing symptoms such as retrosternal burning pain (heartburn). Gastroesophageal Reflux Disease (GERD) (may lead to aspiration pneumonia Aspiration pneumonia A type of lung inflammation resulting from the aspiration of food, liquid, or gastric contents into the upper respiratory tract. Pneumonia) 
• Severe intellectual, speech, and psychomotor disabilities, such as:
  • Delayed sitting up and walking
  • Clumsiness
• Hyperactivity Hyperactivity Attention Deficit Hyperactivity Disorder, aggression Aggression Behavior which may be manifested by destructive and attacking action which is verbal or physical, by covert attitudes of hostility or by obstructionism. Oppositional Defiant Disorder, outbursts, and repetitive movements 
• Unusual facial features:
  • Microcephaly Microcephaly A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed. ). Fetal Alcohol Spectrum Disorder
  • Hypertelorism Hypertelorism Abnormal increase in the interorbital distance due to overdevelopment of the lesser wings of the sphenoid. DiGeorge Syndrome, skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions tags in front of eyes, epicanthal folds, down-slanting palpebral fissures, and strabismus Strabismus Strabismus is the misalignment of the eyes while fixating the gaze on an object. Strabismus can be idiopathic, but it may also be caused by cerebral palsy, uncorrected refractive errors, and extraocular muscle or cranial nerve dysfunction. Strabismus
  • Small, round face with full cheeks Cheeks The part of the face that is below the eye and to the side of the nose and mouth. Melasma 
  • Flat, wide nasal bridge and short philtrum
  • Micrognathia Micrognathia Abnormally small jaw. Pierre Robin Sequence, down-turned mouth, excessive drooling Drooling Peritonsillar Abscess, cleft lip Cleft lip The embryological development of craniofacial structures is an intricate sequential process involving tissue growth and directed cell apoptosis. Disruption of any step in this process may result in the formation of a cleft lip alone or in combination with a cleft palate. As the most common craniofacial malformation of the newborn, the diagnosis of a cleft is clinical and usually apparent at birth. Cleft Lip and Cleft Palate/ palate Palate The palate is the structure that forms the roof of the mouth and floor of the nasal cavity. This structure is divided into soft and hard palates. Palate: Anatomy, and bifid uvula Uvula A fleshy extension at the back of the soft palate that hangs above the opening of the throat. Peritonsillar Abscess
  • Low-set ears Low-set ears DiGeorge Syndrome 
• Hypotonia Hypotonia Duchenne Muscular Dystrophy 
• Constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
• Recurrent infections Recurrent infections Common Variable Immunodeficiency (CVID) (e.g., otitis media, respiratory infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, and urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease [UTIs])
• Clubfeet, syndactyly Syndactyly A congenital anomaly of the hand or foot, marked by the webbing between adjacent fingers or toes. Syndactylies are classified as complete or incomplete by the degree of joining. Syndactylies can also be simple or complex. Simple syndactyly indicates joining of only skin or soft tissue; complex syndactyly marks joining of bony elements. Development of the Limbs, short fingers, and single palmar creases
• Cardiac defects:
  • Ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot
  • Atrial septal defect Atrial Septal Defect Atrial septal defects (ASDs) are benign acyanotic congenital heart defects characterized by an opening in the interatrial septum that causes blood to flow from the left atrium (LA) to the right atrium (RA) (left-to-right shunt). Atrial Septal Defect (ASD)
  • Patent ductus arteriosus Ductus arteriosus A fetal blood vessel connecting the pulmonary artery with the descending aorta. Patent Ductus Arteriosus (PDA)
  • Tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot is the most common cyanotic congenital heart disease. The disease is the confluence of 4 pathologic cardiac features: overriding aorta, ventricular septal defect, right ventricular outflow obstruction, and right ventricular hypertrophy. Tetralogy of Fallot

Symptoms of late childhood and adolescence

• Intellectual disability Disability Determination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits. ABCDE Assessment
• Coarsening of facial features with prominent supraorbital ridges, deep-set eyes, and a hypoplastic nasal bridge 
• Severe dental malocclusion
• Scoliosis Scoliosis Scoliosis is a structural alteration of the vertebral column characterized by a lateral spinal curvature of greater than 10 degrees in the coronal plane. Scoliosis can be classified as idiopathic (in most cases) or secondary to underlying conditions. Scoliosis
• Affected females have normal sexual characteristic development
• In males, the testes Testes Gonadal Hormones are often small, while spermatogenesis Spermatogenesis The process of germ cell development in the male from the primordial germ cells, through spermatogonia; spermatocytes; spermatids; to the mature haploid spermatozoa. Gametogenesis is normal

Diagnosis and Management

Diagnosis

• Distinctive cry and associated physical problems lead to clinical suspicion at birth.
• Genetic counseling Genetic Counseling An educational process that provides information and advice to individuals or families about a genetic condition that may affect them. The purpose is to help individuals make informed decisions about marriage, reproduction, and other health management issues based on information about the genetic disease, the available diagnostic tests, and management programs. Psychosocial support is usually offered. Myotonic Dystrophies and testing ( karyotyping Karyotyping Mapping of the karyotype of a cell. Chromosome Testing) may be offered.
  • If there is high clinical suspicion and the karyotype Karyotype The full set of chromosomes presented as a systematized array of metaphase chromosomes from a photomicrograph of a single cell nucleus arranged in pairs in descending order of size and according to the position of the centromere. Congenital Malformations of the Female Reproductive System is normal, order fluorescence in situ hybridization Fluorescence In Situ Hybridization A type of in situ hybridization in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei. Chromosome Testing ( FISH FISH A type of in situ hybridization in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei. Chromosome Testing) to test for similar syndromes.
• Prenatally, the deletion in chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 5 can be detected through genetic analysis of:
  • Amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity samples
  • Chorionic villi Chorionic villi Threadlike vascular projections of the chorion. Chorionic villi may be free or embedded within the decidua forming the site for exchange of substances between fetal and maternal blood (placenta). Placenta, Umbilical Cord, and Amniotic Cavity samples

Management

• No known cure
• Management aimed at:
  • Maximizing development of affected individuals through speech, physical, and occupational therapy Occupational Therapy Skilled treatment that helps individuals achieve independence in all facets of their lives. It assists in the development of skills needed for independent living. Fetal Alcohol Spectrum Disorder
  • Treating life-threatening conditions (e.g., congenital heart disease)

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas

• Good upon surviving the first few years of life; morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status is low
• Normal life expectancy Life expectancy Based on known statistical data, the number of years which any person of a given age may reasonably expected to live. Population Pyramids possible depending on management and therapies

Differential Diagnosis

The following conditions are differential diagnoses of cri-du-chat syndrome:

• Wolf-Hirschhorn syndrome (Wolf syndrome): a rare chromosomal disorder caused by a partial deletion of the short arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 4, especially of band 4p16.3. Associated abnormalities typically include low birth weight, growth retardation Growth Retardation Failure of a fetus to attain expected growth. Fetal Alcohol Spectrum Disorder, hypotonia Hypotonia Duchenne Muscular Dystrophy, and psychomotor delays and/or disabilities. 
• Mowat-Wilson syndrome Mowat-Wilson syndrome Hirschsprung Disease: a genetic condition caused by mutations in the ZEB2 gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics, characterized by microcephaly Microcephaly A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed. ). Fetal Alcohol Spectrum Disorder, intellectual disability Disability Determination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits. ABCDE Assessment, delayed development, and Hirschsprung’s disease, among other birth defects and distinctive facial features (e.g., a square-shaped face, deep-set and widely spaced eyes, broad nasal bridge, rounded nasal tip, and a prominent and pointed chin Chin The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve. Melasma).
• Patau syndrome Patau syndrome Trisomy 13, or Patau syndrome, is a genetic syndrome caused by the presence of 3 copies of chromosome 13. As the 3rd most common trisomy, Patau syndrome has an incidence of 1 in 10,000 live births. Most cases of Patau syndrome are diagnosed prenatally by maternal screening and ultrasound. More than half of the pregnancies result in spontaneous abortions. Patau Syndrome (Trisomy 13) ( trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 13): a genetic syndrome caused by the presence of 3 copies of the 13th chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics. The condition is characterized by microcephaly Microcephaly A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed. ). Fetal Alcohol Spectrum Disorder, holoprosencephaly Holoprosencephaly Anterior midline brain, cranial, and facial malformations resulting from the failure of the embryonic prosencephalon to undergo segmentation and cleavage. Alobar prosencephaly is the most severe form and features anophthalmia; cyclopia; severe intellectual disability; cleft lip; cleft palate; seizures; and microcephaly. Semilobar holoprosencephaly is characterized by hypotelorism, microphthalmia, coloboma, nasal malformations, and variable degrees of intellectual disability. Lobar holoprosencephaly is associated with mild (or absent) facial malformations and intellectual abilities that range from mild intellectual disability to normal. Holoprosencephaly is associated with chromosome abnormalities. Development of the Nervous System and Face, characteristic facial anomalies (e.g., cleft lip Cleft lip The embryological development of craniofacial structures is an intricate sequential process involving tissue growth and directed cell apoptosis. Disruption of any step in this process may result in the formation of a cleft lip alone or in combination with a cleft palate. As the most common craniofacial malformation of the newborn, the diagnosis of a cleft is clinical and usually apparent at birth. Cleft Lip and Cleft Palate/ palate Palate The palate is the structure that forms the roof of the mouth and floor of the nasal cavity. This structure is divided into soft and hard palates. Palate: Anatomy, low-set, malformed ears, bulbous nose Nose The nose is the human body’s primary organ of smell and functions as part of the upper respiratory system. The nose may be best known for inhaling oxygen and exhaling carbon dioxide, but it also contributes to other important functions, such as tasting. The anatomy of the nose can be divided into the external nose and the nasal cavity. Nose Anatomy (External & Internal), small chin Chin The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve. Melasma, microphthalmia, coloboma Coloboma Congenital anomaly in which some of the structures of the eye are absent due to incomplete fusion of the fetal intraocular fissure during gestation. Esophageal Atresia and Tracheoesophageal Fistula), polydactyly Polydactyly A congenital anomaly of the hand or foot, marked by the presence of supernumerary digits. Physical Examination of the Newborn, and congenital heart defects.
• Fetal alcohol spectrum disorders: a group of conditions that can occur in neonates whose mothers consumed heavy amounts of alcohol during their pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care. Problems may include characteristic craniofacial changes, short height, low body weight, small head size, poor coordination Coordination Cerebellar Disorders, low intelligence, behavior problems, and problems with hearing or seeing. 
• Cohen syndrome: a hereditary disorder with abnormalities that include hypotonia Hypotonia Duchenne Muscular Dystrophy, failure to thrive Failure to Thrive Failure to thrive (FTT), or faltering growth, describes suboptimal weight gain and growth in children. The majority of cases are due to inadequate caloric intake; however, genetic, infectious, and oncological etiologies are also common. Failure to Thrive, microcephaly Microcephaly A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed. ). Fetal Alcohol Spectrum Disorder, joint hypermobility Joint Hypermobility Ehlers-Danlos Syndrome, developmental delay, visual disorders such as myopia Myopia Refractive Errors and strabismus Strabismus Strabismus is the misalignment of the eyes while fixating the gaze on an object. Strabismus can be idiopathic, but it may also be caused by cerebral palsy, uncorrected refractive errors, and extraocular muscle or cranial nerve dysfunction. Strabismus, and characteristic facial features (e.g., arched eyelids Eyelids Each of the upper and lower folds of skin which cover the eye when closed. Blepharitis, low hairline, thick eyelashes and eyebrows, high palate Palate The palate is the structure that forms the roof of the mouth and floor of the nasal cavity. This structure is divided into soft and hard palates. Palate: Anatomy).
• Edwards syndrome Edwards syndrome Edwards syndrome, or trisomy 18, is a genetic syndrome caused by the presence of an extra chromosome 18. The extra chromosome is either from 3 full copies of chromosome 18 or an additional segment of chromosome 18. As the 2nd most common trisomy, Edwards syndrome is seen in 1 out of every 5,500 live births. Edwards Syndrome (Trisomy 18) ( trisomy Trisomy The possession of a third chromosome of any one type in an otherwise diploid cell. Types of Mutations 18): a genetic syndrome caused by the presence of 3 copies of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 18. Associated abnormalities include microcephaly Microcephaly A congenital abnormality in which the cerebrum is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (desk reference for neuroscience, 2nd ed. ). Fetal Alcohol Spectrum Disorder, myelomeningocele, omphalocele Omphalocele Omphalocele is a congenital anterior abdominal wall defect in which the intestines are covered by peritoneum and amniotic membranes. The condition results from the failure of the midgut to return to the abdominal cavity by 10 weeks’ gestation. Omphalocele, malformation of visceral organs such as horseshoe kidney Horseshoe Kidney Congenital Renal Abnormalities and hernias, severe intellectual disability Disability Determination of the degree of a physical, mental, or emotional handicap. The diagnosis is applied to legal qualification for benefits and income under disability insurance and to eligibility for social security and workman’s compensation benefits. ABCDE Assessment, congenital heart defects, and characteristic facial anomalies (e.g., broad nose Nose The nose is the human body’s primary organ of smell and functions as part of the upper respiratory system. The nose may be best known for inhaling oxygen and exhaling carbon dioxide, but it also contributes to other important functions, such as tasting. The anatomy of the nose can be divided into the external nose and the nasal cavity. Nose Anatomy (External & Internal), low-set ears Low-set ears DiGeorge Syndrome, mandibular hypoplasia Hypoplasia Hypoplastic Left Heart Syndrome (HLHS), cleft lip Cleft lip The embryological development of craniofacial structures is an intricate sequential process involving tissue growth and directed cell apoptosis. Disruption of any step in this process may result in the formation of a cleft lip alone or in combination with a cleft palate. As the most common craniofacial malformation of the newborn, the diagnosis of a cleft is clinical and usually apparent at birth. Cleft Lip and Cleft Palate, and palate Palate The palate is the structure that forms the roof of the mouth and floor of the nasal cavity. This structure is divided into soft and hard palates. Palate: Anatomy).